diff --git a/blockchain/reactor.go b/blockchain/reactor.go
index a788c4aca..1ea5650ed 100644
--- a/blockchain/reactor.go
+++ b/blockchain/reactor.go
@@ -6,13 +6,14 @@ import (
 	"reflect"
 	"time"
 
-	cmn "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
-	"github.com/tendermint/tendermint/p2p"
+	"github.com/spf13/viper"
+
 	"github.com/tendermint/go-wire"
+	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 const (
@@ -43,7 +44,7 @@ type consensusReactor interface {
 type BlockchainReactor struct {
 	p2p.BaseReactor
 
-	config       cfg.Config
+	config       *viper.Viper
 	state        *sm.State
 	proxyAppConn proxy.AppConnConsensus // same as consensus.proxyAppConn
 	store        *BlockStore
@@ -57,7 +58,7 @@ type BlockchainReactor struct {
 }
 
 // NewBlockchainReactor returns new reactor instance.
-func NewBlockchainReactor(config cfg.Config, state *sm.State, proxyAppConn proxy.AppConnConsensus, store *BlockStore, fastSync bool) *BlockchainReactor {
+func NewBlockchainReactor(config *viper.Viper, state *sm.State, proxyAppConn proxy.AppConnConsensus, store *BlockStore, fastSync bool) *BlockchainReactor {
 	if state.LastBlockHeight == store.Height()-1 {
 		store.height-- // XXX HACK, make this better
 	}
diff --git a/cmd/tendermint/commands/probe_upnp.go b/cmd/tendermint/commands/probe_upnp.go
index eb55d6690..330dcf17d 100644
--- a/cmd/tendermint/commands/probe_upnp.go
+++ b/cmd/tendermint/commands/probe_upnp.go
@@ -12,14 +12,14 @@ import (
 var probeUpnpCmd = &cobra.Command{
 	Use:   "probe_upnp",
 	Short: "Test UPnP functionality",
-	Run:   probeUpnp,
+	RunE:  probeUpnp,
 }
 
 func init() {
 	RootCmd.AddCommand(probeUpnpCmd)
 }
 
-func probeUpnp(cmd *cobra.Command, args []string) {
+func probeUpnp(cmd *cobra.Command, args []string) error {
 
 	capabilities, err := upnp.Probe()
 	if err != nil {
@@ -28,9 +28,9 @@ func probeUpnp(cmd *cobra.Command, args []string) {
 		fmt.Println("Probe success!")
 		jsonBytes, err := json.Marshal(capabilities)
 		if err != nil {
-			panic(err)
+			return err
 		}
 		fmt.Println(string(jsonBytes))
 	}
-
+	return nil
 }
diff --git a/cmd/tendermint/commands/reset_priv_validator.go b/cmd/tendermint/commands/reset_priv_validator.go
index b1fb334bc..a611935bb 100644
--- a/cmd/tendermint/commands/reset_priv_validator.go
+++ b/cmd/tendermint/commands/reset_priv_validator.go
@@ -4,8 +4,8 @@ import (
 	"os"
 
 	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
 
-	cfg "github.com/tendermint/go-config"
 	"github.com/tendermint/log15"
 	"github.com/tendermint/tendermint/types"
 )
@@ -36,27 +36,30 @@ func resetAll(cmd *cobra.Command, args []string) {
 // XXX: this is totally unsafe.
 // it's only suitable for testnets.
 func resetPrivValidator(cmd *cobra.Command, args []string) {
-	ResetPrivValidator(config, log)
+	resetPrivValidatorLocal(config, log)
 }
 
 // Exported so other CLI tools can use  it
-func ResetAll(c cfg.Config, l log15.Logger) {
-	ResetPrivValidator(c, l)
-	os.RemoveAll(c.GetString("db_dir"))
+func ResetAll(c *viper.Viper, l log15.Logger) {
+	resetPrivValidatorLocal(c, l)
+	dataDir := c.GetString("db_dir")
+	os.RemoveAll(dataDir)
+	l.Notice("Removed all data", "dir", dataDir)
 }
 
-func ResetPrivValidator(c cfg.Config, l log15.Logger) {
+func resetPrivValidatorLocal(c *viper.Viper, l log15.Logger) {
+
 	// Get PrivValidator
 	var privValidator *types.PrivValidator
-	privValidatorFile := config.GetString("priv_validator_file")
+	privValidatorFile := c.GetString("priv_validator_file")
 	if _, err := os.Stat(privValidatorFile); err == nil {
 		privValidator = types.LoadPrivValidator(privValidatorFile)
 		privValidator.Reset()
-		log.Notice("Reset PrivValidator", "file", privValidatorFile)
+		l.Notice("Reset PrivValidator", "file", privValidatorFile)
 	} else {
 		privValidator = types.GenPrivValidator()
 		privValidator.SetFile(privValidatorFile)
 		privValidator.Save()
-		log.Notice("Generated PrivValidator", "file", privValidatorFile)
+		l.Notice("Generated PrivValidator", "file", privValidatorFile)
 	}
 }
diff --git a/cmd/tendermint/commands/root.go b/cmd/tendermint/commands/root.go
index 120d53c04..de5b71bd1 100644
--- a/cmd/tendermint/commands/root.go
+++ b/cmd/tendermint/commands/root.go
@@ -3,8 +3,8 @@ package commands
 import (
 	"github.com/spf13/cobra"
 
-	"github.com/tendermint/tmlibs/logger"
 	tmcfg "github.com/tendermint/tendermint/config/tendermint"
+	"github.com/tendermint/tmlibs/logger"
 )
 
 var (
diff --git a/cmd/tendermint/commands/run_node.go b/cmd/tendermint/commands/run_node.go
index 5e0fef32c..b2b23af5c 100644
--- a/cmd/tendermint/commands/run_node.go
+++ b/cmd/tendermint/commands/run_node.go
@@ -1,21 +1,22 @@
 package commands
 
 import (
+	"fmt"
 	"io/ioutil"
 	"time"
 
 	"github.com/spf13/cobra"
 
-	. "github.com/tendermint/tmlibs/common"
 	"github.com/tendermint/tendermint/node"
 	"github.com/tendermint/tendermint/types"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 var runNodeCmd = &cobra.Command{
 	Use:    "node",
 	Short:  "Run the tendermint node",
 	PreRun: setConfigFlags,
-	Run:    runNode,
+	RunE:   runNode,
 }
 
 //flags
@@ -82,30 +83,30 @@ func setConfigFlags(cmd *cobra.Command, args []string) {
 // should import github.com/tendermint/tendermint/node and implement
 // their own run_node to call node.NewNode (instead of node.NewNodeDefault)
 // with their custom priv validator and/or custom proxy.ClientCreator
-func runNode(cmd *cobra.Command, args []string) {
+func runNode(cmd *cobra.Command, args []string) error {
 
 	// Wait until the genesis doc becomes available
 	// This is for Mintnet compatibility.
 	// TODO: If Mintnet gets deprecated or genesis_file is
 	// always available, remove.
 	genDocFile := config.GetString("genesis_file")
-	if !FileExists(genDocFile) {
-		log.Notice(Fmt("Waiting for genesis file %v...", genDocFile))
+	if !cmn.FileExists(genDocFile) {
+		log.Notice(cmn.Fmt("Waiting for genesis file %v...", genDocFile))
 		for {
 			time.Sleep(time.Second)
-			if !FileExists(genDocFile) {
+			if !cmn.FileExists(genDocFile) {
 				continue
 			}
 			jsonBlob, err := ioutil.ReadFile(genDocFile)
 			if err != nil {
-				Exit(Fmt("Couldn't read GenesisDoc file: %v", err))
+				return fmt.Errorf("Couldn't read GenesisDoc file: %v", err)
 			}
 			genDoc, err := types.GenesisDocFromJSON(jsonBlob)
 			if err != nil {
-				Exit(Fmt("Error reading GenesisDoc: %v", err))
+				return fmt.Errorf("Error reading GenesisDoc: %v", err)
 			}
 			if genDoc.ChainID == "" {
-				Exit(Fmt("Genesis doc %v must include non-empty chain_id", genDocFile))
+				return fmt.Errorf("Genesis doc %v must include non-empty chain_id", genDocFile)
 			}
 			config.Set("chain_id", genDoc.ChainID)
 		}
@@ -114,11 +115,13 @@ func runNode(cmd *cobra.Command, args []string) {
 	// Create & start node
 	n := node.NewNodeDefault(config)
 	if _, err := n.Start(); err != nil {
-		Exit(Fmt("Failed to start node: %v", err))
+		return fmt.Errorf("Failed to start node: %v", err)
 	} else {
 		log.Notice("Started node", "nodeInfo", n.Switch().NodeInfo())
 	}
 
 	// Trap signal, run forever.
 	n.RunForever()
+
+	return nil
 }
diff --git a/config/tendermint/config.go b/config/tendermint/config.go
index 93650eaef..9011e0154 100644
--- a/config/tendermint/config.go
+++ b/config/tendermint/config.go
@@ -5,8 +5,8 @@ import (
 	"path"
 	"strings"
 
-	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
+	"github.com/spf13/viper"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 func getTMRoot(rootDir string) string {
@@ -25,85 +25,89 @@ func getTMRoot(rootDir string) string {
 
 func initTMRoot(rootDir string) {
 	rootDir = getTMRoot(rootDir)
-	EnsureDir(rootDir, 0700)
-	EnsureDir(rootDir+"/data", 0700)
+	cmn.EnsureDir(rootDir, 0700)
+	cmn.EnsureDir(rootDir+"/data", 0700)
 
 	configFilePath := path.Join(rootDir, "config.toml")
 
 	// Write default config file if missing.
-	if !FileExists(configFilePath) {
+	if !cmn.FileExists(configFilePath) {
 		// Ask user for moniker
 		// moniker := cfg.Prompt("Type hostname: ", "anonymous")
-		MustWriteFile(configFilePath, []byte(defaultConfig("anonymous")), 0644)
+		cmn.MustWriteFile(configFilePath, []byte(defaultConfig("anonymous")), 0644)
 	}
 }
 
-func GetConfig(rootDir string) cfg.Config {
+func GetConfig(rootDir string) *viper.Viper {
 	rootDir = getTMRoot(rootDir)
 	initTMRoot(rootDir)
 
-	configFilePath := path.Join(rootDir, "config.toml")
-	mapConfig, err := cfg.ReadMapConfigFromFile(configFilePath)
+	config := viper.New()
+	config.SetConfigName("config")
+	config.SetConfigType("toml")
+	config.AddConfigPath(rootDir)
+	err := config.ReadInConfig()
 	if err != nil {
-		Exit(Fmt("Could not read config: %v", err))
+		cmn.Exit(cmn.Fmt("Could not read config from directory %v: %v", rootDir, err))
 	}
+	//config.WatchConfig()
 
 	// Set defaults or panic
-	if mapConfig.IsSet("chain_id") {
-		Exit("Cannot set 'chain_id' via config.toml")
+	if config.IsSet("chain_id") {
+		cmn.Exit("Cannot set 'chain_id' via config.toml")
 	}
-	if mapConfig.IsSet("revision_file") {
-		Exit("Cannot set 'revision_file' via config.toml. It must match what's in the Makefile")
+	if config.IsSet("revision_file") {
+		cmn.Exit("Cannot set 'revision_file' via config.toml. It must match what's in the Makefile")
 	}
-	mapConfig.SetRequired("chain_id") // blows up if you try to use it before setting.
-	mapConfig.SetDefault("genesis_file", rootDir+"/genesis.json")
-	mapConfig.SetDefault("proxy_app", "tcp://127.0.0.1:46658")
-	mapConfig.SetDefault("abci", "socket")
-	mapConfig.SetDefault("moniker", "anonymous")
-	mapConfig.SetDefault("node_laddr", "tcp://0.0.0.0:46656")
-	mapConfig.SetDefault("seeds", "")
-	// mapConfig.SetDefault("seeds", "goldenalchemist.chaintest.net:46656")
-	mapConfig.SetDefault("fast_sync", true)
-	mapConfig.SetDefault("skip_upnp", false)
-	mapConfig.SetDefault("addrbook_file", rootDir+"/addrbook.json")
-	mapConfig.SetDefault("addrbook_strict", true) // disable to allow connections locally
-	mapConfig.SetDefault("pex_reactor", false)    // enable for peer exchange
-	mapConfig.SetDefault("priv_validator_file", rootDir+"/priv_validator.json")
-	mapConfig.SetDefault("db_backend", "leveldb")
-	mapConfig.SetDefault("db_dir", rootDir+"/data")
-	mapConfig.SetDefault("log_level", "info")
-	mapConfig.SetDefault("rpc_laddr", "tcp://0.0.0.0:46657")
-	mapConfig.SetDefault("grpc_laddr", "")
-	mapConfig.SetDefault("prof_laddr", "")
-	mapConfig.SetDefault("revision_file", rootDir+"/revision")
-	mapConfig.SetDefault("cs_wal_file", rootDir+"/data/cs.wal/wal")
-	mapConfig.SetDefault("cs_wal_light", false)
-	mapConfig.SetDefault("filter_peers", false)
-
-	mapConfig.SetDefault("block_size", 10000)      // max number of txs
-	mapConfig.SetDefault("block_part_size", 65536) // part size 64K
-	mapConfig.SetDefault("disable_data_hash", false)
+	//mapConfig.SetRequired("chain_id") // blows up if you try to use it before setting.
+	config.SetDefault("genesis_file", rootDir+"/genesis.json")
+	config.SetDefault("proxy_app", "tcp://127.0.0.1:46658")
+	config.SetDefault("abci", "socket")
+	config.SetDefault("moniker", "anonymous")
+	config.SetDefault("node_laddr", "tcp://0.0.0.0:46656")
+	config.SetDefault("seeds", "")
+	// config.SetDefault("seeds", "goldenalchemist.chaintest.net:46656")
+	config.SetDefault("fast_sync", true)
+	config.SetDefault("skip_upnp", false)
+	config.SetDefault("addrbook_file", rootDir+"/addrbook.json")
+	config.SetDefault("addrbook_strict", true) // disable to allow connections locally
+	config.SetDefault("pex_reactor", false)    // enable for peer exchange
+	config.SetDefault("priv_validator_file", rootDir+"/priv_validator.json")
+	config.SetDefault("db_backend", "leveldb")
+	config.SetDefault("db_dir", rootDir+"/data")
+	config.SetDefault("log_level", "info")
+	config.SetDefault("rpc_laddr", "tcp://0.0.0.0:46657")
+	config.SetDefault("grpc_laddr", "")
+	config.SetDefault("prof_laddr", "")
+	config.SetDefault("revision_file", rootDir+"/revision")
+	config.SetDefault("cs_wal_file", rootDir+"/data/cs.wal/wal")
+	config.SetDefault("cs_wal_light", false)
+	config.SetDefault("filter_peers", false)
+
+	config.SetDefault("block_size", 10000)      // max number of txs
+	config.SetDefault("block_part_size", 65536) // part size 64K
+	config.SetDefault("disable_data_hash", false)
 
 	// all timeouts are in ms
-	mapConfig.SetDefault("timeout_handshake", 10000)
-	mapConfig.SetDefault("timeout_propose", 3000)
-	mapConfig.SetDefault("timeout_propose_delta", 500)
-	mapConfig.SetDefault("timeout_prevote", 1000)
-	mapConfig.SetDefault("timeout_prevote_delta", 500)
-	mapConfig.SetDefault("timeout_precommit", 1000)
-	mapConfig.SetDefault("timeout_precommit_delta", 500)
-	mapConfig.SetDefault("timeout_commit", 1000)
+	config.SetDefault("timeout_handshake", 10000)
+	config.SetDefault("timeout_propose", 3000)
+	config.SetDefault("timeout_propose_delta", 500)
+	config.SetDefault("timeout_prevote", 1000)
+	config.SetDefault("timeout_prevote_delta", 500)
+	config.SetDefault("timeout_precommit", 1000)
+	config.SetDefault("timeout_precommit_delta", 500)
+	config.SetDefault("timeout_commit", 1000)
 
 	// make progress asap (no `timeout_commit`) on full precommit votes
-	mapConfig.SetDefault("skip_timeout_commit", false)
-	mapConfig.SetDefault("mempool_recheck", true)
-	mapConfig.SetDefault("mempool_recheck_empty", true)
-	mapConfig.SetDefault("mempool_broadcast", true)
-	mapConfig.SetDefault("mempool_wal_dir", rootDir+"/data/mempool.wal")
+	config.SetDefault("skip_timeout_commit", false)
+	config.SetDefault("mempool_recheck", true)
+	config.SetDefault("mempool_recheck_empty", true)
+	config.SetDefault("mempool_broadcast", true)
+	config.SetDefault("mempool_wal_dir", rootDir+"/data/mempool.wal")
 
-	mapConfig.SetDefault("tx_index", "kv")
+	config.SetDefault("tx_index", "kv")
 
-	return mapConfig
+	return config
 }
 
 var defaultConfigTmpl = `# This is a TOML config file.
diff --git a/config/tendermint_test/config.go b/config/tendermint_test/config.go
index fcdc572b9..1a87d5261 100644
--- a/config/tendermint_test/config.go
+++ b/config/tendermint_test/config.go
@@ -3,12 +3,14 @@
 package tendermint_test
 
 import (
+	"fmt"
 	"os"
 	"path"
 	"strings"
 
+	"github.com/spf13/viper"
+
 	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
 	"github.com/tendermint/tmlibs/logger"
 )
 
@@ -43,7 +45,6 @@ func initTMRoot(rootDir string) {
 	// Write default config file if missing.
 	if !FileExists(configFilePath) {
 		// Ask user for moniker
-		// moniker := cfg.Prompt("Type hostname: ", "anonymous")
 		MustWriteFile(configFilePath, []byte(defaultConfig("anonymous")), 0644)
 	}
 	if !FileExists(genesisFilePath) {
@@ -53,65 +54,70 @@ func initTMRoot(rootDir string) {
 	MustWriteFile(privFilePath, []byte(defaultPrivValidator), 0644)
 }
 
-func ResetConfig(localPath string) cfg.Config {
+func ResetConfig(localPath string) *viper.Viper {
 	rootDir := os.Getenv("HOME") + "/.tendermint_test/" + localPath
 	initTMRoot(rootDir)
 
-	configFilePath := path.Join(rootDir, "config.toml")
-	mapConfig, err := cfg.ReadMapConfigFromFile(configFilePath)
+	config := viper.New()
+	config.SetConfigName("config")
+	config.SetConfigType("toml")
+	config.AddConfigPath(rootDir)
+	err := config.ReadInConfig()
 	if err != nil {
 		Exit(Fmt("Could not read config: %v", err))
 	}
+	//config.WatchConfig()
 
 	// Set defaults or panic
-	if mapConfig.IsSet("chain_id") {
-		Exit("Cannot set 'chain_id' via config.toml")
+	if config.IsSet("chain_id") {
+		Exit(fmt.Sprintf("Cannot set 'chain_id' via config.toml:\n %v\n %v\n ", config.Get("chain_id"), rootDir))
 	}
-	mapConfig.SetDefault("chain_id", "tendermint_test")
-	mapConfig.SetDefault("genesis_file", rootDir+"/genesis.json")
-	mapConfig.SetDefault("proxy_app", "dummy")
-	mapConfig.SetDefault("abci", "socket")
-	mapConfig.SetDefault("moniker", "anonymous")
-	mapConfig.SetDefault("node_laddr", "tcp://0.0.0.0:36656")
-	mapConfig.SetDefault("fast_sync", false)
-	mapConfig.SetDefault("skip_upnp", true)
-	mapConfig.SetDefault("addrbook_file", rootDir+"/addrbook.json")
-	mapConfig.SetDefault("addrbook_strict", true) // disable to allow connections locally
-	mapConfig.SetDefault("pex_reactor", false)    // enable for peer exchange
-	mapConfig.SetDefault("priv_validator_file", rootDir+"/priv_validator.json")
-	mapConfig.SetDefault("db_backend", "memdb")
-	mapConfig.SetDefault("db_dir", rootDir+"/data")
-	mapConfig.SetDefault("log_level", "info")
-	mapConfig.SetDefault("rpc_laddr", "tcp://0.0.0.0:36657")
-	mapConfig.SetDefault("grpc_laddr", "tcp://0.0.0.0:36658")
-	mapConfig.SetDefault("prof_laddr", "")
-	mapConfig.SetDefault("revision_file", rootDir+"/revision")
-	mapConfig.SetDefault("cs_wal_file", rootDir+"/data/cs.wal/wal")
-	mapConfig.SetDefault("cs_wal_light", false)
-	mapConfig.SetDefault("filter_peers", false)
-
-	mapConfig.SetDefault("block_size", 10000)
-	mapConfig.SetDefault("block_part_size", 65536) // part size 64K
-	mapConfig.SetDefault("disable_data_hash", false)
-	mapConfig.SetDefault("timeout_handshake", 10000)
-	mapConfig.SetDefault("timeout_propose", 2000)
-	mapConfig.SetDefault("timeout_propose_delta", 1)
-	mapConfig.SetDefault("timeout_prevote", 10)
-	mapConfig.SetDefault("timeout_prevote_delta", 1)
-	mapConfig.SetDefault("timeout_precommit", 10)
-	mapConfig.SetDefault("timeout_precommit_delta", 1)
-	mapConfig.SetDefault("timeout_commit", 10)
-	mapConfig.SetDefault("skip_timeout_commit", true)
-	mapConfig.SetDefault("mempool_recheck", true)
-	mapConfig.SetDefault("mempool_recheck_empty", true)
-	mapConfig.SetDefault("mempool_broadcast", true)
-	mapConfig.SetDefault("mempool_wal_dir", "")
-
-	mapConfig.SetDefault("tx_index", "kv")
-
-	logger.SetLogLevel(mapConfig.GetString("log_level"))
-
-	return mapConfig
+
+	config.SetDefault("chain_id", "tendermint_test")
+	config.SetDefault("genesis_file", rootDir+"/genesis.json")
+	config.SetDefault("proxy_app", "dummy")
+	config.SetDefault("abci", "socket")
+	config.SetDefault("moniker", "anonymous")
+	config.SetDefault("node_laddr", "tcp://0.0.0.0:36656")
+	config.SetDefault("fast_sync", false)
+	config.SetDefault("skip_upnp", true)
+	config.SetDefault("addrbook_file", rootDir+"/addrbook.json")
+	config.SetDefault("addrbook_strict", true) // disable to allow connections locally
+	config.SetDefault("pex_reactor", false)    // enable for peer exchange
+	config.SetDefault("priv_validator_file", rootDir+"/priv_validator.json")
+	config.SetDefault("db_backend", "memdb")
+	config.SetDefault("db_dir", rootDir+"/data")
+	config.SetDefault("log_level", "info")
+	config.SetDefault("rpc_laddr", "tcp://0.0.0.0:36657")
+	config.SetDefault("grpc_laddr", "tcp://0.0.0.0:36658")
+	config.SetDefault("prof_laddr", "")
+	config.SetDefault("revision_file", rootDir+"/revision")
+	config.SetDefault("cs_wal_file", rootDir+"/data/cs.wal/wal")
+	config.SetDefault("cs_wal_light", false)
+	config.SetDefault("filter_peers", false)
+
+	config.SetDefault("block_size", 10000)
+	config.SetDefault("block_part_size", 65536) // part size 64K
+	config.SetDefault("disable_data_hash", false)
+	config.SetDefault("timeout_handshake", 10000)
+	config.SetDefault("timeout_propose", 2000)
+	config.SetDefault("timeout_propose_delta", 1)
+	config.SetDefault("timeout_prevote", 10)
+	config.SetDefault("timeout_prevote_delta", 1)
+	config.SetDefault("timeout_precommit", 10)
+	config.SetDefault("timeout_precommit_delta", 1)
+	config.SetDefault("timeout_commit", 10)
+	config.SetDefault("skip_timeout_commit", true)
+	config.SetDefault("mempool_recheck", true)
+	config.SetDefault("mempool_recheck_empty", true)
+	config.SetDefault("mempool_broadcast", true)
+	config.SetDefault("mempool_wal_dir", "")
+
+	config.SetDefault("tx_index", "kv")
+
+	logger.SetLogLevel(config.GetString("log_level"))
+
+	return config
 }
 
 var defaultConfigTmpl = `# This is a TOML config file.
diff --git a/consensus/byzantine_test.go b/consensus/byzantine_test.go
index acd9e90e2..b9edf4635 100644
--- a/consensus/byzantine_test.go
+++ b/consensus/byzantine_test.go
@@ -5,13 +5,13 @@ import (
 	"testing"
 	"time"
 
-	"github.com/tendermint/tendermint/config/tendermint_test"
+	"github.com/spf13/viper"
 
-	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
-	"github.com/tendermint/tmlibs/events"
+	"github.com/tendermint/tendermint/config/tendermint_test"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/types"
+	. "github.com/tendermint/tmlibs/common"
+	"github.com/tendermint/tmlibs/events"
 )
 
 func init() {
@@ -36,7 +36,7 @@ func TestByzantine(t *testing.T) {
 
 	switches := make([]*p2p.Switch, N)
 	for i := 0; i < N; i++ {
-		switches[i] = p2p.NewSwitch(cfg.NewMapConfig(nil))
+		switches[i] = p2p.NewSwitch(viper.New())
 	}
 
 	reactors := make([]p2p.Reactor, N)
diff --git a/consensus/common_test.go b/consensus/common_test.go
index 77cc8172a..469fc9c6b 100644
--- a/consensus/common_test.go
+++ b/consensus/common_test.go
@@ -11,23 +11,24 @@ import (
 	"testing"
 	"time"
 
+	"github.com/spf13/viper"
+
 	abcicli "github.com/tendermint/abci/client"
 	abci "github.com/tendermint/abci/types"
-	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
-	dbm "github.com/tendermint/tmlibs/db"
-	"github.com/tendermint/tendermint/p2p"
 	bc "github.com/tendermint/tendermint/blockchain"
 	"github.com/tendermint/tendermint/config/tendermint_test"
 	mempl "github.com/tendermint/tendermint/mempool"
+	"github.com/tendermint/tendermint/p2p"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
+	. "github.com/tendermint/tmlibs/common"
+	dbm "github.com/tendermint/tmlibs/db"
 
 	"github.com/tendermint/abci/example/counter"
 	"github.com/tendermint/abci/example/dummy"
 )
 
-var config cfg.Config // NOTE: must be reset for each _test.go file
+var config *viper.Viper // NOTE: must be reset for each _test.go file
 var ensureTimeout = time.Duration(2)
 
 func ensureDir(dir string, mode os.FileMode) {
@@ -233,7 +234,7 @@ func newConsensusState(state *sm.State, pv *types.PrivValidator, app abci.Applic
 	return newConsensusStateWithConfig(config, state, pv, app)
 }
 
-func newConsensusStateWithConfig(thisConfig cfg.Config, state *sm.State, pv *types.PrivValidator, app abci.Application) *ConsensusState {
+func newConsensusStateWithConfig(thisConfig *viper.Viper, state *sm.State, pv *types.PrivValidator, app abci.Application) *ConsensusState {
 	// Get BlockStore
 	blockDB := dbm.NewMemDB()
 	blockStore := bc.NewBlockStore(blockDB)
@@ -256,7 +257,7 @@ func newConsensusStateWithConfig(thisConfig cfg.Config, state *sm.State, pv *typ
 	return cs
 }
 
-func loadPrivValidator(conf cfg.Config) *types.PrivValidator {
+func loadPrivValidator(conf *viper.Viper) *types.PrivValidator {
 	privValidatorFile := conf.GetString("priv_validator_file")
 	ensureDir(path.Dir(privValidatorFile), 0700)
 	privValidator := types.LoadOrGenPrivValidator(privValidatorFile)
diff --git a/consensus/replay.go b/consensus/replay.go
index 931e8893d..5bc0c2611 100644
--- a/consensus/replay.go
+++ b/consensus/replay.go
@@ -10,11 +10,12 @@ import (
 	"strings"
 	"time"
 
+	"github.com/spf13/viper"
+
 	abci "github.com/tendermint/abci/types"
-	auto "github.com/tendermint/tmlibs/autofile"
-	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
 	"github.com/tendermint/go-wire"
+	auto "github.com/tendermint/tmlibs/autofile"
+	cmn "github.com/tendermint/tmlibs/common"
 
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
@@ -108,7 +109,7 @@ func (cs *ConsensusState) catchupReplay(csHeight int) error {
 		gr.Close()
 	}
 	if found {
-		return errors.New(Fmt("WAL should not contain #ENDHEIGHT %d.", csHeight))
+		return errors.New(cmn.Fmt("WAL should not contain #ENDHEIGHT %d.", csHeight))
 	}
 
 	// Search for last height marker
@@ -143,7 +144,7 @@ func (cs *ConsensusState) catchupReplay(csHeight int) error {
 		}
 
 		// TODO (0.10.0): uncomment
-		// return errors.New(Fmt("Cannot replay height %d. WAL does not contain #ENDHEIGHT for %d.", csHeight, csHeight-1))
+		// return errors.New(cmn.Fmt("Cannot replay height %d. WAL does not contain #ENDHEIGHT for %d.", csHeight, csHeight-1))
 	}
 
 	log.Notice("Catchup by replaying consensus messages", "height", csHeight)
@@ -199,14 +200,14 @@ func makeHeightSearchFunc(height int) auto.SearchFunc {
 // we were last and using the WAL to recover there
 
 type Handshaker struct {
-	config cfg.Config
+	config *viper.Viper
 	state  *sm.State
 	store  types.BlockStore
 
 	nBlocks int // number of blocks applied to the state
 }
 
-func NewHandshaker(config cfg.Config, state *sm.State, store types.BlockStore) *Handshaker {
+func NewHandshaker(config *viper.Viper, state *sm.State, store types.BlockStore) *Handshaker {
 	return &Handshaker{config, state, store, 0}
 }
 
@@ -221,7 +222,7 @@ func (h *Handshaker) Handshake(proxyApp proxy.AppConns) error {
 	// handshake is done via info request on the query conn
 	res, err := proxyApp.Query().InfoSync()
 	if err != nil {
-		return errors.New(Fmt("Error calling Info: %v", err))
+		return errors.New(cmn.Fmt("Error calling Info: %v", err))
 	}
 
 	blockHeight := int(res.LastBlockHeight) // XXX: beware overflow
@@ -238,7 +239,7 @@ func (h *Handshaker) Handshake(proxyApp proxy.AppConns) error {
 		return nil
 
 	} else if err != nil {
-		return errors.New(Fmt("Error on replay: %v", err))
+		return errors.New(cmn.Fmt("Error on replay: %v", err))
 	}
 
 	log.Notice("Completed ABCI Handshake - Tendermint and App are synced", "appHeight", blockHeight, "appHash", appHash)
@@ -266,11 +267,11 @@ func (h *Handshaker) ReplayBlocks(appHash []byte, appBlockHeight int, proxyApp p
 
 	} else if storeBlockHeight < stateBlockHeight {
 		// the state should never be ahead of the store (this is under tendermint's control)
-		PanicSanity(Fmt("StateBlockHeight (%d) > StoreBlockHeight (%d)", stateBlockHeight, storeBlockHeight))
+		cmn.PanicSanity(cmn.Fmt("StateBlockHeight (%d) > StoreBlockHeight (%d)", stateBlockHeight, storeBlockHeight))
 
 	} else if storeBlockHeight > stateBlockHeight+1 {
 		// store should be at most one ahead of the state (this is under tendermint's control)
-		PanicSanity(Fmt("StoreBlockHeight (%d) > StateBlockHeight + 1 (%d)", storeBlockHeight, stateBlockHeight+1))
+		cmn.PanicSanity(cmn.Fmt("StoreBlockHeight (%d) > StateBlockHeight + 1 (%d)", storeBlockHeight, stateBlockHeight+1))
 	}
 
 	// Now either store is equal to state, or one ahead.
@@ -313,7 +314,7 @@ func (h *Handshaker) ReplayBlocks(appHash []byte, appBlockHeight int, proxyApp p
 
 	}
 
-	PanicSanity("Should never happen")
+	cmn.PanicSanity("Should never happen")
 	return nil, nil
 }
 
@@ -368,7 +369,7 @@ func (h *Handshaker) replayBlock(height int, proxyApp proxy.AppConnConsensus) ([
 
 func (h *Handshaker) checkAppHash(appHash []byte) error {
 	if !bytes.Equal(h.state.AppHash, appHash) {
-		panic(errors.New(Fmt("Tendermint state.AppHash does not match AppHash after replay. Got %X, expected %X", appHash, h.state.AppHash)).Error())
+		panic(errors.New(cmn.Fmt("Tendermint state.AppHash does not match AppHash after replay. Got %X, expected %X", appHash, h.state.AppHash)).Error())
 		return nil
 	}
 	return nil
diff --git a/consensus/replay_file.go b/consensus/replay_file.go
index 3de0e3d10..1d2a91f31 100644
--- a/consensus/replay_file.go
+++ b/consensus/replay_file.go
@@ -8,24 +8,25 @@ import (
 	"strconv"
 	"strings"
 
-	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
-	dbm "github.com/tendermint/tmlibs/db"
+	"github.com/spf13/viper"
+
 	bc "github.com/tendermint/tendermint/blockchain"
 	mempl "github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
+	cmn "github.com/tendermint/tmlibs/common"
+	dbm "github.com/tendermint/tmlibs/db"
 )
 
 //--------------------------------------------------------
 // replay messages interactively or all at once
 
-func RunReplayFile(config cfg.Config, walFile string, console bool) {
+func RunReplayFile(config *viper.Viper, walFile string, console bool) {
 	consensusState := newConsensusStateForReplay(config)
 
 	if err := consensusState.ReplayFile(walFile, console); err != nil {
-		Exit(Fmt("Error during consensus replay: %v", err))
+		cmn.Exit(cmn.Fmt("Error during consensus replay: %v", err))
 	}
 }
 
@@ -114,7 +115,7 @@ func (pb *playback) replayReset(count int, newStepCh chan interface{}) error {
 	pb.fp = fp
 	pb.scanner = bufio.NewScanner(fp)
 	count = pb.count - count
-	log.Notice(Fmt("Reseting from %d to %d", pb.count, count))
+	log.Notice(cmn.Fmt("Reseting from %d to %d", pb.count, count))
 	pb.count = 0
 	pb.cs = newCS
 	for i := 0; pb.scanner.Scan() && i < count; i++ {
@@ -149,9 +150,9 @@ func (pb *playback) replayConsoleLoop() int {
 		bufReader := bufio.NewReader(os.Stdin)
 		line, more, err := bufReader.ReadLine()
 		if more {
-			Exit("input is too long")
+			cmn.Exit("input is too long")
 		} else if err != nil {
-			Exit(err.Error())
+			cmn.Exit(err.Error())
 		}
 
 		tokens := strings.Split(string(line), " ")
@@ -236,7 +237,7 @@ func (pb *playback) replayConsoleLoop() int {
 //--------------------------------------------------------------------------------
 
 // convenience for replay mode
-func newConsensusStateForReplay(config cfg.Config) *ConsensusState {
+func newConsensusStateForReplay(config *viper.Viper) *ConsensusState {
 	// Get BlockStore
 	blockStoreDB := dbm.NewDB("blockstore", config.GetString("db_backend"), config.GetString("db_dir"))
 	blockStore := bc.NewBlockStore(blockStoreDB)
@@ -249,7 +250,7 @@ func newConsensusStateForReplay(config cfg.Config) *ConsensusState {
 	proxyApp := proxy.NewAppConns(config, proxy.DefaultClientCreator(config), NewHandshaker(config, state, blockStore))
 	_, err := proxyApp.Start()
 	if err != nil {
-		Exit(Fmt("Error starting proxy app conns: %v", err))
+		cmn.Exit(cmn.Fmt("Error starting proxy app conns: %v", err))
 	}
 
 	// add the chainid to the global config
@@ -258,7 +259,7 @@ func newConsensusStateForReplay(config cfg.Config) *ConsensusState {
 	// Make event switch
 	eventSwitch := types.NewEventSwitch()
 	if _, err := eventSwitch.Start(); err != nil {
-		Exit(Fmt("Failed to start event switch: %v", err))
+		cmn.Exit(cmn.Fmt("Failed to start event switch: %v", err))
 	}
 
 	mempool := mempl.NewMempool(config, proxyApp.Mempool())
diff --git a/consensus/replay_test.go b/consensus/replay_test.go
index 32415d6e3..e486af83e 100644
--- a/consensus/replay_test.go
+++ b/consensus/replay_test.go
@@ -12,17 +12,17 @@ import (
 	"testing"
 	"time"
 
-	"github.com/tendermint/tendermint/config/tendermint_test"
+	"github.com/spf13/viper"
 
 	"github.com/tendermint/abci/example/dummy"
-	cmn "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
 	"github.com/tendermint/go-crypto"
-	dbm "github.com/tendermint/tmlibs/db"
 	"github.com/tendermint/go-wire"
+	"github.com/tendermint/tendermint/config/tendermint_test"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
+	cmn "github.com/tendermint/tmlibs/common"
+	dbm "github.com/tendermint/tmlibs/db"
 )
 
 func init() {
@@ -408,7 +408,7 @@ func buildAppStateFromChain(proxyApp proxy.AppConns,
 
 }
 
-func buildTMStateFromChain(config cfg.Config, state *sm.State, chain []*types.Block, mode uint) []byte {
+func buildTMStateFromChain(config *viper.Viper, state *sm.State, chain []*types.Block, mode uint) []byte {
 	// run the whole chain against this client to build up the tendermint state
 	clientCreator := proxy.NewLocalClientCreator(dummy.NewPersistentDummyApplication(path.Join(config.GetString("db_dir"), "1")))
 	proxyApp := proxy.NewAppConns(config, clientCreator, nil) // sm.NewHandshaker(config, state, store, ReplayLastBlock))
@@ -602,7 +602,7 @@ func makeBlockchain(t *testing.T, chainID string, nBlocks int, privVal *types.Pr
 }
 
 // fresh state and mock store
-func stateAndStore(config cfg.Config, pubKey crypto.PubKey) (*sm.State, *mockBlockStore) {
+func stateAndStore(config *viper.Viper, pubKey crypto.PubKey) (*sm.State, *mockBlockStore) {
 	stateDB := dbm.NewMemDB()
 	return sm.MakeGenesisState(stateDB, &types.GenesisDoc{
 		ChainID: config.GetString("chain_id"),
@@ -617,13 +617,13 @@ func stateAndStore(config cfg.Config, pubKey crypto.PubKey) (*sm.State, *mockBlo
 // mock block store
 
 type mockBlockStore struct {
-	config  cfg.Config
+	config  *viper.Viper
 	chain   []*types.Block
 	commits []*types.Commit
 }
 
 // TODO: NewBlockStore(db.NewMemDB) ...
-func NewMockBlockStore(config cfg.Config) *mockBlockStore {
+func NewMockBlockStore(config *viper.Viper) *mockBlockStore {
 	return &mockBlockStore{config, nil, nil}
 }
 
diff --git a/consensus/state.go b/consensus/state.go
index 8077dcec1..28836a079 100644
--- a/consensus/state.go
+++ b/consensus/state.go
@@ -10,13 +10,13 @@ import (
 	"time"
 
 	"github.com/ebuchman/fail-test"
+	"github.com/spf13/viper"
 
-	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
 	"github.com/tendermint/go-wire"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 //-----------------------------------------------------------------------------
@@ -56,7 +56,7 @@ func (tp *TimeoutParams) Commit(t time.Time) time.Time {
 }
 
 // InitTimeoutParamsFromConfig initializes parameters from config
-func InitTimeoutParamsFromConfig(config cfg.Config) *TimeoutParams {
+func InitTimeoutParamsFromConfig(config *viper.Viper) *TimeoutParams {
 	return &TimeoutParams{
 		Propose0:          config.GetInt("timeout_propose"),
 		ProposeDelta:      config.GetInt("timeout_propose_delta"),
@@ -222,9 +222,9 @@ type PrivValidator interface {
 
 // Tracks consensus state across block heights and rounds.
 type ConsensusState struct {
-	BaseService
+	cmn.BaseService
 
-	config       cfg.Config
+	config       *viper.Viper
 	proxyAppConn proxy.AppConnConsensus
 	blockStore   types.BlockStore
 	mempool      types.Mempool
@@ -255,7 +255,7 @@ type ConsensusState struct {
 	done chan struct{}
 }
 
-func NewConsensusState(config cfg.Config, state *sm.State, proxyAppConn proxy.AppConnConsensus, blockStore types.BlockStore, mempool types.Mempool) *ConsensusState {
+func NewConsensusState(config *viper.Viper, state *sm.State, proxyAppConn proxy.AppConnConsensus, blockStore types.BlockStore, mempool types.Mempool) *ConsensusState {
 	cs := &ConsensusState{
 		config:           config,
 		proxyAppConn:     proxyAppConn,
@@ -276,7 +276,7 @@ func NewConsensusState(config cfg.Config, state *sm.State, proxyAppConn proxy.Ap
 	// Don't call scheduleRound0 yet.
 	// We do that upon Start().
 	cs.reconstructLastCommit(state)
-	cs.BaseService = *NewBaseService(log, "ConsensusState", cs)
+	cs.BaseService = *cmn.NewBaseService(log, "ConsensusState", cs)
 	return cs
 }
 
@@ -290,7 +290,7 @@ func (cs *ConsensusState) SetEventSwitch(evsw types.EventSwitch) {
 
 func (cs *ConsensusState) String() string {
 	// better not to access shared variables
-	return Fmt("ConsensusState") //(H:%v R:%v S:%v", cs.Height, cs.Round, cs.Step)
+	return cmn.Fmt("ConsensusState") //(H:%v R:%v S:%v", cs.Height, cs.Round, cs.Step)
 }
 
 func (cs *ConsensusState) GetState() *sm.State {
@@ -398,7 +398,7 @@ func (cs *ConsensusState) Wait() {
 
 // Open file to log all consensus messages and timeouts for deterministic accountability
 func (cs *ConsensusState) OpenWAL(walFile string) (err error) {
-	err = EnsureDir(path.Dir(walFile), 0700)
+	err = cmn.EnsureDir(path.Dir(walFile), 0700)
 	if err != nil {
 		log.Error("Error ensuring ConsensusState wal dir", "error", err.Error())
 		return err
@@ -519,11 +519,11 @@ func (cs *ConsensusState) reconstructLastCommit(state *sm.State) {
 		}
 		added, err := lastPrecommits.AddVote(precommit)
 		if !added || err != nil {
-			PanicCrisis(Fmt("Failed to reconstruct LastCommit: %v", err))
+			cmn.PanicCrisis(cmn.Fmt("Failed to reconstruct LastCommit: %v", err))
 		}
 	}
 	if !lastPrecommits.HasTwoThirdsMajority() {
-		PanicSanity("Failed to reconstruct LastCommit: Does not have +2/3 maj")
+		cmn.PanicSanity("Failed to reconstruct LastCommit: Does not have +2/3 maj")
 	}
 	cs.LastCommit = lastPrecommits
 }
@@ -532,13 +532,13 @@ func (cs *ConsensusState) reconstructLastCommit(state *sm.State) {
 // The round becomes 0 and cs.Step becomes RoundStepNewHeight.
 func (cs *ConsensusState) updateToState(state *sm.State) {
 	if cs.CommitRound > -1 && 0 < cs.Height && cs.Height != state.LastBlockHeight {
-		PanicSanity(Fmt("updateToState() expected state height of %v but found %v",
+		cmn.PanicSanity(cmn.Fmt("updateToState() expected state height of %v but found %v",
 			cs.Height, state.LastBlockHeight))
 	}
 	if cs.state != nil && cs.state.LastBlockHeight+1 != cs.Height {
 		// This might happen when someone else is mutating cs.state.
 		// Someone forgot to pass in state.Copy() somewhere?!
-		PanicSanity(Fmt("Inconsistent cs.state.LastBlockHeight+1 %v vs cs.Height %v",
+		cmn.PanicSanity(cmn.Fmt("Inconsistent cs.state.LastBlockHeight+1 %v vs cs.Height %v",
 			cs.state.LastBlockHeight+1, cs.Height))
 	}
 
@@ -555,7 +555,7 @@ func (cs *ConsensusState) updateToState(state *sm.State) {
 	lastPrecommits := (*types.VoteSet)(nil)
 	if cs.CommitRound > -1 && cs.Votes != nil {
 		if !cs.Votes.Precommits(cs.CommitRound).HasTwoThirdsMajority() {
-			PanicSanity("updateToState(state) called but last Precommit round didn't have +2/3")
+			cmn.PanicSanity("updateToState(state) called but last Precommit round didn't have +2/3")
 		}
 		lastPrecommits = cs.Votes.Precommits(cs.CommitRound)
 	}
@@ -723,7 +723,7 @@ func (cs *ConsensusState) handleTimeout(ti timeoutInfo, rs RoundState) {
 		types.FireEventTimeoutWait(cs.evsw, cs.RoundStateEvent())
 		cs.enterNewRound(ti.Height, ti.Round+1)
 	default:
-		panic(Fmt("Invalid timeout step: %v", ti.Step))
+		panic(cmn.Fmt("Invalid timeout step: %v", ti.Step))
 	}
 
 }
@@ -738,7 +738,7 @@ func (cs *ConsensusState) handleTimeout(ti timeoutInfo, rs RoundState) {
 // NOTE: cs.StartTime was already set for height.
 func (cs *ConsensusState) enterNewRound(height int, round int) {
 	if cs.Height != height || round < cs.Round || (cs.Round == round && cs.Step != RoundStepNewHeight) {
-		log.Debug(Fmt("enterNewRound(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+		log.Debug(cmn.Fmt("enterNewRound(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
 	}
 
@@ -746,7 +746,7 @@ func (cs *ConsensusState) enterNewRound(height int, round int) {
 		log.Warn("Need to set a buffer and log.Warn() here for sanity.", "startTime", cs.StartTime, "now", now)
 	}
 
-	log.Notice(Fmt("enterNewRound(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+	log.Notice(cmn.Fmt("enterNewRound(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 
 	// Increment validators if necessary
 	validators := cs.Validators
@@ -780,10 +780,10 @@ func (cs *ConsensusState) enterNewRound(height int, round int) {
 // Enter: from NewRound(height,round).
 func (cs *ConsensusState) enterPropose(height int, round int) {
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPropose <= cs.Step) {
-		log.Debug(Fmt("enterPropose(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+		log.Debug(cmn.Fmt("enterPropose(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
 	}
-	log.Info(Fmt("enterPropose(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+	log.Info(cmn.Fmt("enterPropose(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 
 	defer func() {
 		// Done enterPropose:
@@ -850,7 +850,7 @@ func (cs *ConsensusState) defaultDecideProposal(height, round int) {
 			cs.sendInternalMessage(msgInfo{&BlockPartMessage{cs.Height, cs.Round, part}, ""})
 		}
 		log.Info("Signed proposal", "height", height, "round", round, "proposal", proposal)
-		log.Debug(Fmt("Signed proposal block: %v", block))
+		log.Debug(cmn.Fmt("Signed proposal block: %v", block))
 	} else {
 		if !cs.replayMode {
 			log.Warn("enterPropose: Error signing proposal", "height", height, "round", round, "error", err)
@@ -906,7 +906,7 @@ func (cs *ConsensusState) createProposalBlock() (block *types.Block, blockParts
 // Otherwise vote nil.
 func (cs *ConsensusState) enterPrevote(height int, round int) {
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPrevote <= cs.Step) {
-		log.Debug(Fmt("enterPrevote(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+		log.Debug(cmn.Fmt("enterPrevote(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
 	}
 
@@ -924,7 +924,7 @@ func (cs *ConsensusState) enterPrevote(height int, round int) {
 		// TODO: catchup event?
 	}
 
-	log.Info(Fmt("enterPrevote(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+	log.Info(cmn.Fmt("enterPrevote(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 
 	// Sign and broadcast vote as necessary
 	cs.doPrevote(height, round)
@@ -967,13 +967,13 @@ func (cs *ConsensusState) defaultDoPrevote(height int, round int) {
 // Enter: any +2/3 prevotes at next round.
 func (cs *ConsensusState) enterPrevoteWait(height int, round int) {
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPrevoteWait <= cs.Step) {
-		log.Debug(Fmt("enterPrevoteWait(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+		log.Debug(cmn.Fmt("enterPrevoteWait(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
 	}
 	if !cs.Votes.Prevotes(round).HasTwoThirdsAny() {
-		PanicSanity(Fmt("enterPrevoteWait(%v/%v), but Prevotes does not have any +2/3 votes", height, round))
+		cmn.PanicSanity(cmn.Fmt("enterPrevoteWait(%v/%v), but Prevotes does not have any +2/3 votes", height, round))
 	}
-	log.Info(Fmt("enterPrevoteWait(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+	log.Info(cmn.Fmt("enterPrevoteWait(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 
 	defer func() {
 		// Done enterPrevoteWait:
@@ -993,11 +993,11 @@ func (cs *ConsensusState) enterPrevoteWait(height int, round int) {
 // else, precommit nil otherwise.
 func (cs *ConsensusState) enterPrecommit(height int, round int) {
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPrecommit <= cs.Step) {
-		log.Debug(Fmt("enterPrecommit(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+		log.Debug(cmn.Fmt("enterPrecommit(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
 	}
 
-	log.Info(Fmt("enterPrecommit(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+	log.Info(cmn.Fmt("enterPrecommit(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 
 	defer func() {
 		// Done enterPrecommit:
@@ -1024,7 +1024,7 @@ func (cs *ConsensusState) enterPrecommit(height int, round int) {
 	// the latest POLRound should be this round
 	polRound, _ := cs.Votes.POLInfo()
 	if polRound < round {
-		PanicSanity(Fmt("This POLRound should be %v but got %", round, polRound))
+		cmn.PanicSanity(cmn.Fmt("This POLRound should be %v but got %", round, polRound))
 	}
 
 	// +2/3 prevoted nil. Unlock and precommit nil.
@@ -1058,7 +1058,7 @@ func (cs *ConsensusState) enterPrecommit(height int, round int) {
 		log.Notice("enterPrecommit: +2/3 prevoted proposal block. Locking", "hash", blockID.Hash)
 		// Validate the block.
 		if err := cs.state.ValidateBlock(cs.ProposalBlock); err != nil {
-			PanicConsensus(Fmt("enterPrecommit: +2/3 prevoted for an invalid block: %v", err))
+			cmn.PanicConsensus(cmn.Fmt("enterPrecommit: +2/3 prevoted for an invalid block: %v", err))
 		}
 		cs.LockedRound = round
 		cs.LockedBlock = cs.ProposalBlock
@@ -1087,13 +1087,13 @@ func (cs *ConsensusState) enterPrecommit(height int, round int) {
 // Enter: any +2/3 precommits for next round.
 func (cs *ConsensusState) enterPrecommitWait(height int, round int) {
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPrecommitWait <= cs.Step) {
-		log.Debug(Fmt("enterPrecommitWait(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+		log.Debug(cmn.Fmt("enterPrecommitWait(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
 	}
 	if !cs.Votes.Precommits(round).HasTwoThirdsAny() {
-		PanicSanity(Fmt("enterPrecommitWait(%v/%v), but Precommits does not have any +2/3 votes", height, round))
+		cmn.PanicSanity(cmn.Fmt("enterPrecommitWait(%v/%v), but Precommits does not have any +2/3 votes", height, round))
 	}
-	log.Info(Fmt("enterPrecommitWait(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
+	log.Info(cmn.Fmt("enterPrecommitWait(%v/%v). Current: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 
 	defer func() {
 		// Done enterPrecommitWait:
@@ -1109,10 +1109,10 @@ func (cs *ConsensusState) enterPrecommitWait(height int, round int) {
 // Enter: +2/3 precommits for block
 func (cs *ConsensusState) enterCommit(height int, commitRound int) {
 	if cs.Height != height || RoundStepCommit <= cs.Step {
-		log.Debug(Fmt("enterCommit(%v/%v): Invalid args. Current step: %v/%v/%v", height, commitRound, cs.Height, cs.Round, cs.Step))
+		log.Debug(cmn.Fmt("enterCommit(%v/%v): Invalid args. Current step: %v/%v/%v", height, commitRound, cs.Height, cs.Round, cs.Step))
 		return
 	}
-	log.Info(Fmt("enterCommit(%v/%v). Current: %v/%v/%v", height, commitRound, cs.Height, cs.Round, cs.Step))
+	log.Info(cmn.Fmt("enterCommit(%v/%v). Current: %v/%v/%v", height, commitRound, cs.Height, cs.Round, cs.Step))
 
 	defer func() {
 		// Done enterCommit:
@@ -1128,7 +1128,7 @@ func (cs *ConsensusState) enterCommit(height int, commitRound int) {
 
 	blockID, ok := cs.Votes.Precommits(commitRound).TwoThirdsMajority()
 	if !ok {
-		PanicSanity("RunActionCommit() expects +2/3 precommits")
+		cmn.PanicSanity("RunActionCommit() expects +2/3 precommits")
 	}
 
 	// The Locked* fields no longer matter.
@@ -1155,7 +1155,7 @@ func (cs *ConsensusState) enterCommit(height int, commitRound int) {
 // If we have the block AND +2/3 commits for it, finalize.
 func (cs *ConsensusState) tryFinalizeCommit(height int) {
 	if cs.Height != height {
-		PanicSanity(Fmt("tryFinalizeCommit() cs.Height: %v vs height: %v", cs.Height, height))
+		cmn.PanicSanity(cmn.Fmt("tryFinalizeCommit() cs.Height: %v vs height: %v", cs.Height, height))
 	}
 
 	blockID, ok := cs.Votes.Precommits(cs.CommitRound).TwoThirdsMajority()
@@ -1176,7 +1176,7 @@ func (cs *ConsensusState) tryFinalizeCommit(height int) {
 // Increment height and goto RoundStepNewHeight
 func (cs *ConsensusState) finalizeCommit(height int) {
 	if cs.Height != height || cs.Step != RoundStepCommit {
-		log.Debug(Fmt("finalizeCommit(%v): Invalid args. Current step: %v/%v/%v", height, cs.Height, cs.Round, cs.Step))
+		log.Debug(cmn.Fmt("finalizeCommit(%v): Invalid args. Current step: %v/%v/%v", height, cs.Height, cs.Round, cs.Step))
 		return
 	}
 
@@ -1184,21 +1184,21 @@ func (cs *ConsensusState) finalizeCommit(height int) {
 	block, blockParts := cs.ProposalBlock, cs.ProposalBlockParts
 
 	if !ok {
-		PanicSanity(Fmt("Cannot finalizeCommit, commit does not have two thirds majority"))
+		cmn.PanicSanity(cmn.Fmt("Cannot finalizeCommit, commit does not have two thirds majority"))
 	}
 	if !blockParts.HasHeader(blockID.PartsHeader) {
-		PanicSanity(Fmt("Expected ProposalBlockParts header to be commit header"))
+		cmn.PanicSanity(cmn.Fmt("Expected ProposalBlockParts header to be commit header"))
 	}
 	if !block.HashesTo(blockID.Hash) {
-		PanicSanity(Fmt("Cannot finalizeCommit, ProposalBlock does not hash to commit hash"))
+		cmn.PanicSanity(cmn.Fmt("Cannot finalizeCommit, ProposalBlock does not hash to commit hash"))
 	}
 	if err := cs.state.ValidateBlock(block); err != nil {
-		PanicConsensus(Fmt("+2/3 committed an invalid block: %v", err))
+		cmn.PanicConsensus(cmn.Fmt("+2/3 committed an invalid block: %v", err))
 	}
 
-	log.Notice(Fmt("Finalizing commit of block with %d txs", block.NumTxs),
+	log.Notice(cmn.Fmt("Finalizing commit of block with %d txs", block.NumTxs),
 		"height", block.Height, "hash", block.Hash(), "root", block.AppHash)
-	log.Info(Fmt("%v", block))
+	log.Info(cmn.Fmt("%v", block))
 
 	fail.Fail() // XXX
 
@@ -1393,7 +1393,7 @@ func (cs *ConsensusState) addVote(vote *types.Vote, peerKey string) (added bool,
 		}
 		added, err = cs.LastCommit.AddVote(vote)
 		if added {
-			log.Info(Fmt("Added to lastPrecommits: %v", cs.LastCommit.StringShort()))
+			log.Info(cmn.Fmt("Added to lastPrecommits: %v", cs.LastCommit.StringShort()))
 			types.FireEventVote(cs.evsw, types.EventDataVote{vote})
 
 			// if we can skip timeoutCommit and have all the votes now,
@@ -1474,7 +1474,7 @@ func (cs *ConsensusState) addVote(vote *types.Vote, peerKey string) (added bool,
 					cs.enterPrecommitWait(height, vote.Round)
 				}
 			default:
-				PanicSanity(Fmt("Unexpected vote type %X", vote.Type)) // Should not happen.
+				cmn.PanicSanity(cmn.Fmt("Unexpected vote type %X", vote.Type)) // Should not happen.
 			}
 		}
 		// Either duplicate, or error upon cs.Votes.AddByIndex()
diff --git a/glide.lock b/glide.lock
index 954064e5c..7720c946b 100644
--- a/glide.lock
+++ b/glide.lock
@@ -1,18 +1,18 @@
-hash: 9096fc4e29eff8fac3708ed30deacac67b7a181f0192b177006105dccdb16686
-updated: 2017-04-21T18:39:37.154946943-04:00
+hash: 6f8962f6ca0e25b8e43bc6e496bd46c9ff3a79dcf789578efeeaee2fffc39c6e
+updated: 2017-04-25T14:48:36.999444976-04:00
 imports:
 - name: github.com/btcsuite/btcd
   version: 583684b21bfbde9b5fc4403916fd7c807feb0289
   subpackages:
   - btcec
-- name: github.com/BurntSushi/toml
-  version: 99064174e013895bbd9b025c31100bd1d9b590ca
 - name: github.com/davecgh/go-spew
   version: 6d212800a42e8ab5c146b8ace3490ee17e5225f9
   subpackages:
   - spew
 - name: github.com/ebuchman/fail-test
   version: 95f809107225be108efcf10a3509e4ea6ceef3c4
+- name: github.com/fsnotify/fsnotify
+  version: 4da3e2cfbabc9f751898f250b49f2439785783a1
 - name: github.com/go-stack/stack
   version: 100eb0c0a9c5b306ca2fb4f165df21d80ada4b82
 - name: github.com/gogo/protobuf
@@ -27,24 +27,53 @@ imports:
   version: d9eb7a3d35ec988b8585d4a0068e462c27d28380
 - name: github.com/gorilla/websocket
   version: 3ab3a8b8831546bd18fd182c20687ca853b2bb13
+- name: github.com/hashicorp/hcl
+  version: 630949a3c5fa3c613328e1b8256052cbc2327c9b
+  subpackages:
+  - hcl/ast
+  - hcl/parser
+  - hcl/scanner
+  - hcl/strconv
+  - hcl/token
+  - json/parser
+  - json/scanner
+  - json/token
 - name: github.com/inconshreveable/mousetrap
   version: 76626ae9c91c4f2a10f34cad8ce83ea42c93bb75
 - name: github.com/jmhodges/levigo
   version: c42d9e0ca023e2198120196f842701bb4c55d7b9
+- name: github.com/magiconair/properties
+  version: 51463bfca2576e06c62a8504b5c0f06d61312647
 - name: github.com/mattn/go-colorable
   version: d228849504861217f796da67fae4f6e347643f15
 - name: github.com/mattn/go-isatty
   version: 30a891c33c7cde7b02a981314b4228ec99380cca
+- name: github.com/mitchellh/mapstructure
+  version: 53818660ed4955e899c0bcafa97299a388bd7c8e
+- name: github.com/pelletier/go-buffruneio
+  version: c37440a7cf42ac63b919c752ca73a85067e05992
+- name: github.com/pelletier/go-toml
+  version: 13d49d4606eb801b8f01ae542b4afc4c6ee3d84a
 - name: github.com/pkg/errors
   version: 645ef00459ed84a119197bfb8d8205042c6df63d
 - name: github.com/pmezard/go-difflib
   version: d8ed2627bdf02c080bf22230dbb337003b7aba2d
   subpackages:
   - difflib
+- name: github.com/spf13/afero
+  version: 9be650865eab0c12963d8753212f4f9c66cdcf12
+  subpackages:
+  - mem
+- name: github.com/spf13/cast
+  version: acbeb36b902d72a7a4c18e8f3241075e7ab763e4
 - name: github.com/spf13/cobra
   version: fcd0c5a1df88f5d6784cb4feead962c3f3d0b66c
+- name: github.com/spf13/jwalterweatherman
+  version: fa7ca7e836cf3a8bb4ebf799f472c12d7e903d66
 - name: github.com/spf13/pflag
   version: 9ff6c6923cfffbcd502984b8e0c80539a94968b7
+- name: github.com/spf13/viper
+  version: 5d46e70da8c0b6f812e0b170b7a985753b5c63cb
 - name: github.com/stretchr/testify
   version: 69483b4bd14f5845b5a1e55bca19e954e827f1d0
   subpackages:
@@ -66,7 +95,7 @@ imports:
   - leveldb/table
   - leveldb/util
 - name: github.com/tendermint/abci
-  version: be61e273cebeb64866a83c578f92b22cf2169cdd
+  version: c709d3cc857929a8dd36a90da3640122d7e75770
   subpackages:
   - client
   - example/counter
@@ -78,10 +107,6 @@ imports:
   subpackages:
   - edwards25519
   - extra25519
-- name: github.com/tendermint/go-common
-  version: f9e3db037330c8a8d61d3966de8473eaf01154fa
-- name: github.com/tendermint/go-config
-  version: 620dcbbd7d587cf3599dedbf329b64311b0c307a
 - name: github.com/tendermint/go-crypto
   version: 9b95da8fa4187f6799558d89b271dc8ab6485615
 - name: github.com/tendermint/go-wire
@@ -136,6 +161,11 @@ imports:
   version: d75a52659825e75fff6158388dddc6a5b04f9ba5
   subpackages:
   - unix
+- name: golang.org/x/text
+  version: f4b4367115ec2de254587813edaa901bc1c723a8
+  subpackages:
+  - transform
+  - unicode/norm
 - name: google.golang.org/grpc
   version: cbcceb2942a489498cf22b2f918536e819d33f0a
   subpackages:
@@ -149,4 +179,6 @@ imports:
   - stats
   - tap
   - transport
+- name: gopkg.in/yaml.v2
+  version: cd8b52f8269e0feb286dfeef29f8fe4d5b397e0b
 testImports: []
diff --git a/glide.yaml b/glide.yaml
index a5570d038..f06a16b3b 100644
--- a/glide.yaml
+++ b/glide.yaml
@@ -10,6 +10,7 @@ import:
 - package: github.com/gorilla/websocket
 - package: github.com/pkg/errors
 - package: github.com/spf13/cobra
+- package: github.com/spf13/viper
 - package: github.com/stretchr/testify
   subpackages:
   - require
@@ -19,8 +20,6 @@ import:
   - client
   - example/dummy
   - types
-- package: github.com/tendermint/go-config
-  version: develop
 - package: github.com/tendermint/go-crypto
   version: develop
 - package: github.com/tendermint/go-wire
diff --git a/mempool/mempool.go b/mempool/mempool.go
index eedf6fb9c..621f0931e 100644
--- a/mempool/mempool.go
+++ b/mempool/mempool.go
@@ -7,13 +7,14 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/spf13/viper"
+
 	abci "github.com/tendermint/abci/types"
+	"github.com/tendermint/tendermint/proxy"
+	"github.com/tendermint/tendermint/types"
 	auto "github.com/tendermint/tmlibs/autofile"
 	"github.com/tendermint/tmlibs/clist"
 	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
-	"github.com/tendermint/tendermint/proxy"
-	"github.com/tendermint/tendermint/types"
 )
 
 /*
@@ -47,7 +48,7 @@ TODO: Better handle abci client errors. (make it automatically handle connection
 const cacheSize = 100000
 
 type Mempool struct {
-	config cfg.Config
+	config *viper.Viper
 
 	proxyMtx      sync.Mutex
 	proxyAppConn  proxy.AppConnMempool
@@ -66,7 +67,7 @@ type Mempool struct {
 	wal *auto.AutoFile
 }
 
-func NewMempool(config cfg.Config, proxyAppConn proxy.AppConnMempool) *Mempool {
+func NewMempool(config *viper.Viper, proxyAppConn proxy.AppConnMempool) *Mempool {
 	mempool := &Mempool{
 		config:        config,
 		proxyAppConn:  proxyAppConn,
diff --git a/mempool/reactor.go b/mempool/reactor.go
index 4d1638888..6bea53b0c 100644
--- a/mempool/reactor.go
+++ b/mempool/reactor.go
@@ -6,12 +6,13 @@ import (
 	"reflect"
 	"time"
 
+	"github.com/spf13/viper"
+
 	abci "github.com/tendermint/abci/types"
-	"github.com/tendermint/tmlibs/clist"
-	cfg "github.com/tendermint/go-config"
-	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/go-wire"
+	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/types"
+	"github.com/tendermint/tmlibs/clist"
 )
 
 const (
@@ -24,12 +25,12 @@ const (
 // MempoolReactor handles mempool tx broadcasting amongst peers.
 type MempoolReactor struct {
 	p2p.BaseReactor
-	config  cfg.Config
+	config  *viper.Viper
 	Mempool *Mempool
 	evsw    types.EventSwitch
 }
 
-func NewMempoolReactor(config cfg.Config, mempool *Mempool) *MempoolReactor {
+func NewMempoolReactor(config *viper.Viper, mempool *Mempool) *MempoolReactor {
 	memR := &MempoolReactor{
 		config:  config,
 		Mempool: mempool,
diff --git a/node/node.go b/node/node.go
index f24c1c4f2..1c66c00e0 100644
--- a/node/node.go
+++ b/node/node.go
@@ -7,19 +7,18 @@ import (
 	"net/http"
 	"strings"
 
+	"github.com/spf13/viper"
+
 	abci "github.com/tendermint/abci/types"
-	cmn "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
 	crypto "github.com/tendermint/go-crypto"
-	dbm "github.com/tendermint/tmlibs/db"
-	p2p "github.com/tendermint/tendermint/p2p"
-	rpc "github.com/tendermint/tendermint/rpc"
-	rpcserver "github.com/tendermint/tendermint/rpc/server"
 	wire "github.com/tendermint/go-wire"
 	bc "github.com/tendermint/tendermint/blockchain"
 	"github.com/tendermint/tendermint/consensus"
 	mempl "github.com/tendermint/tendermint/mempool"
+	p2p "github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/proxy"
+	rpc "github.com/tendermint/tendermint/rpc"
+	rpcserver "github.com/tendermint/tendermint/rpc/server"
 	rpccore "github.com/tendermint/tendermint/rpc/tendermint/core"
 	grpccore "github.com/tendermint/tendermint/rpc/tendermint/grpc"
 	sm "github.com/tendermint/tendermint/state"
@@ -28,6 +27,8 @@ import (
 	"github.com/tendermint/tendermint/state/txindex/null"
 	"github.com/tendermint/tendermint/types"
 	"github.com/tendermint/tendermint/version"
+	cmn "github.com/tendermint/tmlibs/common"
+	dbm "github.com/tendermint/tmlibs/db"
 
 	_ "net/http/pprof"
 )
@@ -36,7 +37,7 @@ type Node struct {
 	cmn.BaseService
 
 	// config
-	config        cfg.Config           // user config
+	config        *viper.Viper         // user config
 	genesisDoc    *types.GenesisDoc    // initial validator set
 	privValidator *types.PrivValidator // local node's validator key
 
@@ -57,14 +58,14 @@ type Node struct {
 	txIndexer        txindex.TxIndexer
 }
 
-func NewNodeDefault(config cfg.Config) *Node {
+func NewNodeDefault(config *viper.Viper) *Node {
 	// Get PrivValidator
 	privValidatorFile := config.GetString("priv_validator_file")
 	privValidator := types.LoadOrGenPrivValidator(privValidatorFile)
 	return NewNode(config, privValidator, proxy.DefaultClientCreator(config))
 }
 
-func NewNode(config cfg.Config, privValidator *types.PrivValidator, clientCreator proxy.ClientCreator) *Node {
+func NewNode(config *viper.Viper, privValidator *types.PrivValidator, clientCreator proxy.ClientCreator) *Node {
 
 	// Get BlockStore
 	blockStoreDB := dbm.NewDB("blockstore", config.GetString("db_backend"), config.GetString("db_dir"))
@@ -134,7 +135,11 @@ func NewNode(config cfg.Config, privValidator *types.PrivValidator, clientCreato
 	consensusReactor := consensus.NewConsensusReactor(consensusState, fastSync)
 
 	// Make p2p network switch
-	sw := p2p.NewSwitch(config.GetConfig("p2p"))
+	p2pConfig := viper.New()
+	if config.IsSet("p2p") { //TODO verify this necessary, where is this ever set?
+		p2pConfig = config.Get("p2p").(*viper.Viper)
+	}
+	sw := p2p.NewSwitch(p2pConfig)
 	sw.AddReactor("MEMPOOL", mempoolReactor)
 	sw.AddReactor("BLOCKCHAIN", bcReactor)
 	sw.AddReactor("CONSENSUS", consensusReactor)
diff --git a/p2p/config.go b/p2p/config.go
index a8b7e343b..2e70d16df 100644
--- a/p2p/config.go
+++ b/p2p/config.go
@@ -1,7 +1,7 @@
 package p2p
 
 import (
-	cfg "github.com/tendermint/go-config"
+	"github.com/spf13/viper"
 )
 
 const (
@@ -24,7 +24,7 @@ const (
 	configFuzzProbSleep            = "fuzz_prob_sleep"
 )
 
-func setConfigDefaults(config cfg.Config) {
+func setConfigDefaults(config *viper.Viper) {
 	// Switch default config
 	config.SetDefault(configKeyDialTimeoutSeconds, 3)
 	config.SetDefault(configKeyHandshakeTimeoutSeconds, 20)
diff --git a/p2p/switch.go b/p2p/switch.go
index 8c771df1c..7e9c0a9c6 100644
--- a/p2p/switch.go
+++ b/p2p/switch.go
@@ -7,7 +7,8 @@ import (
 	"net"
 	"time"
 
-	cfg "github.com/tendermint/go-config"
+	"github.com/spf13/viper"
+
 	crypto "github.com/tendermint/go-crypto"
 	"github.com/tendermint/log15"
 	. "github.com/tendermint/tmlibs/common"
@@ -61,7 +62,7 @@ incoming messages are received on the reactor.
 type Switch struct {
 	BaseService
 
-	config       cfg.Config
+	config       *viper.Viper
 	listeners    []Listener
 	reactors     map[string]Reactor
 	chDescs      []*ChannelDescriptor
@@ -80,7 +81,7 @@ var (
 	ErrSwitchMaxPeersPerIPRange = errors.New("IP range has too many peers")
 )
 
-func NewSwitch(config cfg.Config) *Switch {
+func NewSwitch(config *viper.Viper) *Switch {
 	setConfigDefaults(config)
 
 	sw := &Switch{
@@ -529,7 +530,7 @@ func makeSwitch(i int, network, version string, initSwitch func(int, *Switch) *S
 	privKey := crypto.GenPrivKeyEd25519()
 	// new switch, add reactors
 	// TODO: let the config be passed in?
-	s := initSwitch(i, NewSwitch(cfg.NewMapConfig(nil)))
+	s := initSwitch(i, NewSwitch(viper.New()))
 	s.SetNodeInfo(&NodeInfo{
 		PubKey:     privKey.PubKey().Unwrap().(crypto.PubKeyEd25519),
 		Moniker:    Fmt("switch%d", i),
@@ -572,7 +573,7 @@ func (sw *Switch) addPeerWithConnectionAndConfig(conn net.Conn, config *PeerConf
 	return nil
 }
 
-func peerConfigFromGoConfig(config cfg.Config) *PeerConfig {
+func peerConfigFromGoConfig(config *viper.Viper) *PeerConfig {
 	return &PeerConfig{
 		AuthEnc:          config.GetBool(configKeyAuthEnc),
 		Fuzz:             config.GetBool(configFuzzEnable),
diff --git a/p2p/switch_test.go b/p2p/switch_test.go
index 1f1fe69f0..38529d754 100644
--- a/p2p/switch_test.go
+++ b/p2p/switch_test.go
@@ -8,20 +8,21 @@ import (
 	"testing"
 	"time"
 
+	"github.com/spf13/viper"
+
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
 	crypto "github.com/tendermint/go-crypto"
 	wire "github.com/tendermint/go-wire"
+	. "github.com/tendermint/tmlibs/common"
 )
 
 var (
-	config cfg.Config
+	config *viper.Viper
 )
 
 func init() {
-	config = cfg.NewMapConfig(nil)
+	config = viper.New()
 	setConfigDefaults(config)
 }
 
diff --git a/proxy/app_conn_test.go b/proxy/app_conn_test.go
index 7c072625a..f9c6afc98 100644
--- a/proxy/app_conn_test.go
+++ b/proxy/app_conn_test.go
@@ -4,11 +4,11 @@ import (
 	"strings"
 	"testing"
 
-	. "github.com/tendermint/tmlibs/common"
 	abcicli "github.com/tendermint/abci/client"
 	"github.com/tendermint/abci/example/dummy"
 	"github.com/tendermint/abci/server"
 	"github.com/tendermint/abci/types"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 //----------------------------------------
@@ -44,43 +44,43 @@ func (app *appConnTest) InfoSync() (types.ResponseInfo, error) {
 var SOCKET = "socket"
 
 func TestEcho(t *testing.T) {
-	sockPath := Fmt("unix:///tmp/echo_%v.sock", RandStr(6))
+	sockPath := cmn.Fmt("unix:///tmp/echo_%v.sock", cmn.RandStr(6))
 	clientCreator := NewRemoteClientCreator(sockPath, SOCKET, true)
 
 	// Start server
 	s, err := server.NewSocketServer(sockPath, dummy.NewDummyApplication())
 	if err != nil {
-		Exit(err.Error())
+		cmn.Exit(err.Error())
 	}
 	defer s.Stop()
 	// Start client
 	cli, err := clientCreator.NewABCIClient()
 	if err != nil {
-		Exit(err.Error())
+		cmn.Exit(err.Error())
 	}
 	proxy := NewAppConnTest(cli)
 	t.Log("Connected")
 
 	for i := 0; i < 1000; i++ {
-		proxy.EchoAsync(Fmt("echo-%v", i))
+		proxy.EchoAsync(cmn.Fmt("echo-%v", i))
 	}
 	proxy.FlushSync()
 }
 
 func BenchmarkEcho(b *testing.B) {
 	b.StopTimer() // Initialize
-	sockPath := Fmt("unix:///tmp/echo_%v.sock", RandStr(6))
+	sockPath := cmn.Fmt("unix:///tmp/echo_%v.sock", cmn.RandStr(6))
 	clientCreator := NewRemoteClientCreator(sockPath, SOCKET, true)
 	// Start server
 	s, err := server.NewSocketServer(sockPath, dummy.NewDummyApplication())
 	if err != nil {
-		Exit(err.Error())
+		cmn.Exit(err.Error())
 	}
 	defer s.Stop()
 	// Start client
 	cli, err := clientCreator.NewABCIClient()
 	if err != nil {
-		Exit(err.Error())
+		cmn.Exit(err.Error())
 	}
 	proxy := NewAppConnTest(cli)
 	b.Log("Connected")
@@ -98,18 +98,18 @@ func BenchmarkEcho(b *testing.B) {
 }
 
 func TestInfo(t *testing.T) {
-	sockPath := Fmt("unix:///tmp/echo_%v.sock", RandStr(6))
+	sockPath := cmn.Fmt("unix:///tmp/echo_%v.sock", cmn.RandStr(6))
 	clientCreator := NewRemoteClientCreator(sockPath, SOCKET, true)
 	// Start server
 	s, err := server.NewSocketServer(sockPath, dummy.NewDummyApplication())
 	if err != nil {
-		Exit(err.Error())
+		cmn.Exit(err.Error())
 	}
 	defer s.Stop()
 	// Start client
 	cli, err := clientCreator.NewABCIClient()
 	if err != nil {
-		Exit(err.Error())
+		cmn.Exit(err.Error())
 	}
 	proxy := NewAppConnTest(cli)
 	t.Log("Connected")
diff --git a/proxy/client.go b/proxy/client.go
index ea9051989..4c50f38b3 100644
--- a/proxy/client.go
+++ b/proxy/client.go
@@ -4,10 +4,11 @@ import (
 	"fmt"
 	"sync"
 
+	"github.com/spf13/viper"
+
 	abcicli "github.com/tendermint/abci/client"
 	"github.com/tendermint/abci/example/dummy"
 	"github.com/tendermint/abci/types"
-	cfg "github.com/tendermint/go-config"
 )
 
 // NewABCIClient returns newly connected client
@@ -63,7 +64,7 @@ func (r *remoteClientCreator) NewABCIClient() (abcicli.Client, error) {
 //-----------------------------------------------------------------
 // default
 
-func DefaultClientCreator(config cfg.Config) ClientCreator {
+func DefaultClientCreator(config *viper.Viper) ClientCreator {
 	addr := config.GetString("proxy_app")
 	transport := config.GetString("abci")
 
diff --git a/proxy/multi_app_conn.go b/proxy/multi_app_conn.go
index b70a0baf0..9f70713eb 100644
--- a/proxy/multi_app_conn.go
+++ b/proxy/multi_app_conn.go
@@ -1,8 +1,8 @@
 package proxy
 
 import (
+	"github.com/spf13/viper"
 	cmn "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
 )
 
 //-----------------------------
@@ -16,7 +16,7 @@ type AppConns interface {
 	Query() AppConnQuery
 }
 
-func NewAppConns(config cfg.Config, clientCreator ClientCreator, handshaker Handshaker) AppConns {
+func NewAppConns(config *viper.Viper, clientCreator ClientCreator, handshaker Handshaker) AppConns {
 	return NewMultiAppConn(config, clientCreator, handshaker)
 }
 
@@ -34,7 +34,7 @@ type Handshaker interface {
 type multiAppConn struct {
 	cmn.BaseService
 
-	config cfg.Config
+	config *viper.Viper
 
 	handshaker Handshaker
 
@@ -46,7 +46,7 @@ type multiAppConn struct {
 }
 
 // Make all necessary abci connections to the application
-func NewMultiAppConn(config cfg.Config, clientCreator ClientCreator, handshaker Handshaker) *multiAppConn {
+func NewMultiAppConn(config *viper.Viper, clientCreator ClientCreator, handshaker Handshaker) *multiAppConn {
 	multiAppConn := &multiAppConn{
 		config:        config,
 		handshaker:    handshaker,
diff --git a/rpc/tendermint/core/pipe.go b/rpc/tendermint/core/pipe.go
index d4a1d127e..b10ff4737 100644
--- a/rpc/tendermint/core/pipe.go
+++ b/rpc/tendermint/core/pipe.go
@@ -1,11 +1,11 @@
 package core
 
 import (
-	cfg "github.com/tendermint/go-config"
+	"github.com/spf13/viper"
 
 	crypto "github.com/tendermint/go-crypto"
-	p2p "github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/consensus"
+	p2p "github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/proxy"
 	"github.com/tendermint/tendermint/state/txindex"
 	"github.com/tendermint/tendermint/types"
@@ -34,7 +34,7 @@ var (
 	// external, thread safe interfaces
 	eventSwitch   types.EventSwitch
 	proxyAppQuery proxy.AppConnQuery
-	config        cfg.Config
+	config        *viper.Viper
 
 	// interfaces defined in types and above
 	blockStore     types.BlockStore
@@ -49,7 +49,7 @@ var (
 	txIndexer txindex.TxIndexer
 )
 
-func SetConfig(c cfg.Config) {
+func SetConfig(c *viper.Viper) {
 	config = c
 }
 
diff --git a/rpc/tendermint/core/routes.go b/rpc/tendermint/core/routes.go
index 1ed874f28..7ed18ef7f 100644
--- a/rpc/tendermint/core/routes.go
+++ b/rpc/tendermint/core/routes.go
@@ -3,8 +3,8 @@ package core
 import (
 	data "github.com/tendermint/go-wire/data"
 	rpc "github.com/tendermint/tendermint/rpc/server"
-	"github.com/tendermint/tendermint/rpc/types"
 	ctypes "github.com/tendermint/tendermint/rpc/tendermint/core/types"
+	"github.com/tendermint/tendermint/rpc/types"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -39,7 +39,9 @@ var Routes = map[string]*rpc.RPCFunc{
 	// control API
 	"dial_seeds":           rpc.NewRPCFunc(UnsafeDialSeedsResult, "seeds"),
 	"unsafe_flush_mempool": rpc.NewRPCFunc(UnsafeFlushMempool, ""),
-	"unsafe_set_config":    rpc.NewRPCFunc(UnsafeSetConfigResult, "type,key,value"),
+
+	// config is not in general thread safe. expose specifics if you need em
+	// "unsafe_set_config":    rpc.NewRPCFunc(UnsafeSetConfigResult, "type,key,value"),
 
 	// profiler API
 	"unsafe_start_cpu_profiler": rpc.NewRPCFunc(UnsafeStartCPUProfilerResult, "filename"),
diff --git a/rpc/tendermint/test/client_test.go b/rpc/tendermint/test/client_test.go
index 1164bdd79..11ee61a56 100644
--- a/rpc/tendermint/test/client_test.go
+++ b/rpc/tendermint/test/client_test.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
 	abci "github.com/tendermint/abci/types"
 	rpc "github.com/tendermint/tendermint/rpc/client"
 	"github.com/tendermint/tendermint/rpc/tendermint/core"
@@ -66,8 +67,8 @@ func TestJSONBroadcastTxSync(t *testing.T) {
 }
 
 func testBroadcastTxSync(t *testing.T, client rpc.HTTPClient) {
-	config.Set("block_size", 0)
-	defer config.Set("block_size", -1)
+	mem := node.MempoolReactor().Mempool
+	initMemSize := mem.Size()
 	tmResult := new(ctypes.TMResult)
 	tx := randBytes(t)
 	_, err := client.Call("broadcast_tx_sync", map[string]interface{}{"tx": tx}, tmResult)
@@ -75,8 +76,7 @@ func testBroadcastTxSync(t *testing.T, client rpc.HTTPClient) {
 
 	res := (*tmResult).(*ctypes.ResultBroadcastTx)
 	require.Equal(t, abci.CodeType_OK, res.Code)
-	mem := node.MempoolReactor().Mempool
-	require.Equal(t, 1, mem.Size())
+	require.Equal(t, initMemSize+1, mem.Size())
 	txs := mem.Reap(1)
 	require.EqualValues(t, tx, txs[0])
 	mem.Flush()
@@ -357,51 +357,52 @@ func TestWSDoubleFire(t *testing.T) {
 }*/
 
 //--------------------------------------------------------------------------------
+//TODO needs to be refactored so we don't use a mutable config but rather update specific values we're interested in
 // unsafe_set_config
 
-var stringVal = "my string"
-var intVal = 987654321
-var boolVal = true
-
-// don't change these
-var testCasesUnsafeSetConfig = [][]string{
-	[]string{"string", "key1", stringVal},
-	[]string{"int", "key2", fmt.Sprintf("%v", intVal)},
-	[]string{"bool", "key3", fmt.Sprintf("%v", boolVal)},
-}
-
-func TestURIUnsafeSetConfig(t *testing.T) {
-	for _, testCase := range testCasesUnsafeSetConfig {
-		tmResult := new(ctypes.TMResult)
-		_, err := GetURIClient().Call("unsafe_set_config", map[string]interface{}{
-			"type":  testCase[0],
-			"key":   testCase[1],
-			"value": testCase[2],
-		}, tmResult)
-		require.Nil(t, err)
-	}
-	testUnsafeSetConfig(t)
-}
-
-func TestJSONUnsafeSetConfig(t *testing.T) {
-	for _, testCase := range testCasesUnsafeSetConfig {
-		tmResult := new(ctypes.TMResult)
-		_, err := GetJSONClient().Call("unsafe_set_config",
-			map[string]interface{}{"type": testCase[0], "key": testCase[1], "value": testCase[2]},
-			tmResult)
-		require.Nil(t, err)
-	}
-	testUnsafeSetConfig(t)
-}
-
-func testUnsafeSetConfig(t *testing.T) {
-	require := require.New(t)
-	s := config.GetString("key1")
-	require.Equal(stringVal, s)
-
-	i := config.GetInt("key2")
-	require.Equal(intVal, i)
-
-	b := config.GetBool("key3")
-	require.Equal(boolVal, b)
-}
+//var stringVal = "my string"
+//var intVal = 987654321
+//var boolVal = true
+//
+//// don't change these
+//var testCasesUnsafeSetConfig = [][]string{
+//	[]string{"string", "key1", stringVal},
+//	[]string{"int", "key2", fmt.Sprintf("%v", intVal)},
+//	[]string{"bool", "key3", fmt.Sprintf("%v", boolVal)},
+//}
+//
+//func TestURIUnsafeSetConfig(t *testing.T) {
+//	for _, testCase := range testCasesUnsafeSetConfig {
+//		tmResult := new(ctypes.TMResult)
+//		_, err := GetURIClient().Call("unsafe_set_config", map[string]interface{}{
+//			"type":  testCase[0],
+//			"key":   testCase[1],
+//			"value": testCase[2],
+//		}, tmResult)
+//		require.Nil(t, err)
+//	}
+//	testUnsafeSetConfig(t)
+//}
+//
+//func TestJSONUnsafeSetConfig(t *testing.T) {
+//	for _, testCase := range testCasesUnsafeSetConfig {
+//		tmResult := new(ctypes.TMResult)
+//		_, err := GetJSONClient().Call("unsafe_set_config",
+//			map[string]interface{}{"type": testCase[0], "key": testCase[1], "value": testCase[2]},
+//			tmResult)
+//		require.Nil(t, err)
+//	}
+//	testUnsafeSetConfig(t)
+//}
+//
+//func testUnsafeSetConfig(t *testing.T) {
+//	require := require.New(t)
+//	s := config.GetString("key1")
+//	require.Equal(stringVal, s)
+//
+//	i := config.GetInt("key2")
+//	require.Equal(intVal, i)
+//
+//	b := config.GetBool("key3")
+//	require.Equal(boolVal, b)
+//}
diff --git a/rpc/tendermint/test/helpers.go b/rpc/tendermint/test/helpers.go
index e5a2fb4e2..4e281f8c3 100644
--- a/rpc/tendermint/test/helpers.go
+++ b/rpc/tendermint/test/helpers.go
@@ -9,24 +9,22 @@ import (
 	"testing"
 	"time"
 
+	"github.com/spf13/viper"
 	"github.com/stretchr/testify/require"
-	logger "github.com/tendermint/tmlibs/logger"
 	wire "github.com/tendermint/go-wire"
+	logger "github.com/tendermint/tmlibs/logger"
 
 	abci "github.com/tendermint/abci/types"
-	cfg "github.com/tendermint/go-config"
-	client "github.com/tendermint/tendermint/rpc/client"
 	"github.com/tendermint/tendermint/config/tendermint_test"
 	nm "github.com/tendermint/tendermint/node"
 	"github.com/tendermint/tendermint/proxy"
+	client "github.com/tendermint/tendermint/rpc/client"
 	ctypes "github.com/tendermint/tendermint/rpc/tendermint/core/types"
 	core_grpc "github.com/tendermint/tendermint/rpc/tendermint/grpc"
 	"github.com/tendermint/tendermint/types"
 )
 
-var (
-	config cfg.Config
-)
+var config *viper.Viper
 
 const tmLogLevel = "error"
 
@@ -56,7 +54,7 @@ func makeAddrs() (string, string, string) {
 }
 
 // GetConfig returns a config for the test cases as a singleton
-func GetConfig() cfg.Config {
+func GetConfig() *viper.Viper {
 	if config == nil {
 		pathname := makePathname()
 		config = tendermint_test.ResetConfig(pathname)
diff --git a/state/errors.go b/state/errors.go
index 1ea7ed3d9..50c5a2c04 100644
--- a/state/errors.go
+++ b/state/errors.go
@@ -1,7 +1,7 @@
 package state
 
 import (
-	. "github.com/tendermint/tmlibs/common"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 type (
@@ -36,20 +36,20 @@ type (
 )
 
 func (e ErrUnknownBlock) Error() string {
-	return Fmt("Could not find block #%d", e.Height)
+	return cmn.Fmt("Could not find block #%d", e.Height)
 }
 
 func (e ErrBlockHashMismatch) Error() string {
-	return Fmt("App block hash (%X) does not match core block hash (%X) for height %d", e.AppHash, e.CoreHash, e.Height)
+	return cmn.Fmt("App block hash (%X) does not match core block hash (%X) for height %d", e.AppHash, e.CoreHash, e.Height)
 }
 
 func (e ErrAppBlockHeightTooHigh) Error() string {
-	return Fmt("App block height (%d) is higher than core (%d)", e.AppHeight, e.CoreHeight)
+	return cmn.Fmt("App block height (%d) is higher than core (%d)", e.AppHeight, e.CoreHeight)
 }
 func (e ErrLastStateMismatch) Error() string {
-	return Fmt("Latest tendermint block (%d) LastAppHash (%X) does not match app's AppHash (%X)", e.Height, e.Core, e.App)
+	return cmn.Fmt("Latest tendermint block (%d) LastAppHash (%X) does not match app's AppHash (%X)", e.Height, e.Core, e.App)
 }
 
 func (e ErrStateMismatch) Error() string {
-	return Fmt("State after replay does not match saved state. Got ----\n%v\nExpected ----\n%v\n", e.Got, e.Expected)
+	return cmn.Fmt("State after replay does not match saved state. Got ----\n%v\nExpected ----\n%v\n", e.Got, e.Expected)
 }
diff --git a/state/execution.go b/state/execution.go
index 643dd4d05..b06974cd8 100644
--- a/state/execution.go
+++ b/state/execution.go
@@ -6,11 +6,11 @@ import (
 
 	fail "github.com/ebuchman/fail-test"
 	abci "github.com/tendermint/abci/types"
-	. "github.com/tendermint/tmlibs/common"
 	crypto "github.com/tendermint/go-crypto"
 	"github.com/tendermint/tendermint/proxy"
 	"github.com/tendermint/tendermint/state/txindex"
 	"github.com/tendermint/tendermint/types"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 //--------------------------------------------------
@@ -126,7 +126,7 @@ func updateValidators(validators *types.ValidatorSet, changedValidators []*abci.
 		power := int64(v.Power)
 		// mind the overflow from uint64
 		if power < 0 {
-			return errors.New(Fmt("Power (%d) overflows int64", v.Power))
+			return errors.New(cmn.Fmt("Power (%d) overflows int64", v.Power))
 		}
 
 		_, val := validators.GetByAddress(address)
@@ -134,20 +134,20 @@ func updateValidators(validators *types.ValidatorSet, changedValidators []*abci.
 			// add val
 			added := validators.Add(types.NewValidator(pubkey, power))
 			if !added {
-				return errors.New(Fmt("Failed to add new validator %X with voting power %d", address, power))
+				return errors.New(cmn.Fmt("Failed to add new validator %X with voting power %d", address, power))
 			}
 		} else if v.Power == 0 {
 			// remove val
 			_, removed := validators.Remove(address)
 			if !removed {
-				return errors.New(Fmt("Failed to remove validator %X)"))
+				return errors.New(cmn.Fmt("Failed to remove validator %X)"))
 			}
 		} else {
 			// update val
 			val.VotingPower = power
 			updated := validators.Update(val)
 			if !updated {
-				return errors.New(Fmt("Failed to update validator %X with voting power %d", address, power))
+				return errors.New(cmn.Fmt("Failed to update validator %X with voting power %d", address, power))
 			}
 		}
 	}
@@ -156,8 +156,8 @@ func updateValidators(validators *types.ValidatorSet, changedValidators []*abci.
 
 // return a bit array of validators that signed the last commit
 // NOTE: assumes commits have already been authenticated
-func commitBitArrayFromBlock(block *types.Block) *BitArray {
-	signed := NewBitArray(len(block.LastCommit.Precommits))
+func commitBitArrayFromBlock(block *types.Block) *cmn.BitArray {
+	signed := cmn.NewBitArray(len(block.LastCommit.Precommits))
 	for i, precommit := range block.LastCommit.Precommits {
 		if precommit != nil {
 			signed.SetIndex(i, true) // val_.LastCommitHeight = block.Height - 1
@@ -187,7 +187,7 @@ func (s *State) validateBlock(block *types.Block) error {
 		}
 	} else {
 		if len(block.LastCommit.Precommits) != s.LastValidators.Size() {
-			return errors.New(Fmt("Invalid block commit size. Expected %v, got %v",
+			return errors.New(cmn.Fmt("Invalid block commit size. Expected %v, got %v",
 				s.LastValidators.Size(), len(block.LastCommit.Precommits)))
 		}
 		err := s.LastValidators.VerifyCommit(
diff --git a/state/state.go b/state/state.go
index ccdf508ac..2625cbc71 100644
--- a/state/state.go
+++ b/state/state.go
@@ -6,10 +6,11 @@ import (
 	"sync"
 	"time"
 
+	"github.com/spf13/viper"
 	abci "github.com/tendermint/abci/types"
-	. "github.com/tendermint/tmlibs/common"
-	cfg "github.com/tendermint/go-config"
+	cmn "github.com/tendermint/tmlibs/common"
 	dbm "github.com/tendermint/tmlibs/db"
+
 	"github.com/tendermint/go-wire"
 	"github.com/tendermint/tendermint/state/txindex"
 	"github.com/tendermint/tendermint/state/txindex/null"
@@ -64,7 +65,7 @@ func loadState(db dbm.DB, key []byte) *State {
 		wire.ReadBinaryPtr(&s, r, 0, n, err)
 		if *err != nil {
 			// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-			Exit(Fmt("LoadState: Data has been corrupted or its spec has changed: %v\n", *err))
+			cmn.Exit(cmn.Fmt("LoadState: Data has been corrupted or its spec has changed: %v\n", *err))
 		}
 		// TODO: ensure that buf is completely read.
 	}
@@ -108,7 +109,7 @@ func (s *State) LoadABCIResponses() *ABCIResponses {
 		wire.ReadBinaryPtr(abciResponses, r, 0, n, err)
 		if *err != nil {
 			// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-			Exit(Fmt("LoadABCIResponses: Data has been corrupted or its spec has changed: %v\n", *err))
+			cmn.Exit(cmn.Fmt("LoadABCIResponses: Data has been corrupted or its spec has changed: %v\n", *err))
 		}
 		// TODO: ensure that buf is completely read.
 	}
@@ -123,7 +124,7 @@ func (s *State) Bytes() []byte {
 	buf, n, err := new(bytes.Buffer), new(int), new(error)
 	wire.WriteBinary(s, buf, n, err)
 	if *err != nil {
-		PanicCrisis(*err)
+		cmn.PanicCrisis(*err)
 	}
 	return buf.Bytes()
 }
@@ -168,7 +169,7 @@ func (s *State) GetValidators() (*types.ValidatorSet, *types.ValidatorSet) {
 
 // Load the most recent state from "state" db,
 // or create a new one (and save) from genesis.
-func GetState(config cfg.Config, stateDB dbm.DB) *State {
+func GetState(config *viper.Viper, stateDB dbm.DB) *State {
 	state := LoadState(stateDB)
 	if state == nil {
 		state = MakeGenesisStateFromFile(stateDB, config.GetString("genesis_file"))
@@ -203,7 +204,7 @@ func (a *ABCIResponses) Bytes() []byte {
 	buf, n, err := new(bytes.Buffer), new(int), new(error)
 	wire.WriteBinary(*a, buf, n, err)
 	if *err != nil {
-		PanicCrisis(*err)
+		cmn.PanicCrisis(*err)
 	}
 	return buf.Bytes()
 }
@@ -217,11 +218,11 @@ func (a *ABCIResponses) Bytes() []byte {
 func MakeGenesisStateFromFile(db dbm.DB, genDocFile string) *State {
 	genDocJSON, err := ioutil.ReadFile(genDocFile)
 	if err != nil {
-		Exit(Fmt("Couldn't read GenesisDoc file: %v", err))
+		cmn.Exit(cmn.Fmt("Couldn't read GenesisDoc file: %v", err))
 	}
 	genDoc, err := types.GenesisDocFromJSON(genDocJSON)
 	if err != nil {
-		Exit(Fmt("Error reading GenesisDoc: %v", err))
+		cmn.Exit(cmn.Fmt("Error reading GenesisDoc: %v", err))
 	}
 	return MakeGenesisState(db, genDoc)
 }
@@ -231,7 +232,7 @@ func MakeGenesisStateFromFile(db dbm.DB, genDocFile string) *State {
 // Used in tests.
 func MakeGenesisState(db dbm.DB, genDoc *types.GenesisDoc) *State {
 	if len(genDoc.Validators) == 0 {
-		Exit(Fmt("The genesis file has no validators"))
+		cmn.Exit(cmn.Fmt("The genesis file has no validators"))
 	}
 
 	if genDoc.GenesisTime.IsZero() {
diff --git a/test/test_libs.sh b/test/test_libs.sh
index 1d57ae049..3f4315cd9 100644
--- a/test/test_libs.sh
+++ b/test/test_libs.sh
@@ -14,8 +14,8 @@ fi
 
 # some libs are tested with go, others with make
 # TODO: should be all make (post repo merge)
-LIBS_GO_TEST=(tmlibs/clist tmlibs/common go-config go-crypto tmlibs/db tmlibs/events go-merkle tendermint/p2p)
-LIBS_MAKE_TEST=(tendermint/rpc go-wire abci)
+LIBS_GO_TEST=(tmlibs go-crypto)
+LIBS_MAKE_TEST=(go-wire abci)
 
 for lib in "${LIBS_GO_TEST[@]}"; do