diff --git a/proxy/proxy_app.go b/proxy/proxy_app.go
new file mode 100644
index 000000000..10afee609
--- /dev/null
+++ b/proxy/proxy_app.go
@@ -0,0 +1,349 @@
+package proxy
+
+import (
+	"bufio"
+	"container/list"
+	"errors"
+	"fmt"
+	"net"
+	"reflect"
+	"sync"
+
+	. "github.com/tendermint/go-common"
+	"github.com/tendermint/go-wire"
+	tmsp "github.com/tendermint/tmsp/types"
+)
+
+const maxResponseSize = 1048576 // 1MB
+
+// This is goroutine-safe, but users should beware that
+// the application in general is not meant to be interfaced
+// with concurrent callers.
+// In other words, the mempool and consensus modules need to
+// exclude each other w/ an external mutex.
+type ProxyApp struct {
+	QuitService
+	sync.Mutex
+
+	reqQueue chan QueuedRequest
+
+	mtx            sync.Mutex
+	conn           net.Conn
+	bufWriter      *bufio.Writer
+	err            error
+	reqSent        *list.List
+	reqPending     *list.Element // Next element in reqSent waiting for response
+	resReceived    *list.List
+	eventsReceived *list.List
+}
+
+func NewProxyApp(conn net.Conn, bufferSize int) *ProxyApp {
+	p := &ProxyApp{
+		reqQueue:       make(chan QueuedRequest, bufferSize),
+		conn:           conn,
+		bufWriter:      bufio.NewWriter(conn),
+		reqSent:        list.New(),
+		reqPending:     nil,
+		resReceived:    list.New(),
+		eventsReceived: list.New(),
+	}
+	p.QuitService = *NewQuitService(nil, "ProxyApp", p)
+	return p
+}
+
+func (p *ProxyApp) OnStart() error {
+	p.QuitService.OnStart()
+	go p.sendRequestsRoutine()
+	go p.recvResponseRoutine()
+	return nil
+}
+
+func (p *ProxyApp) OnStop() {
+	p.QuitService.OnStop()
+	p.conn.Close()
+}
+
+func (p *ProxyApp) StopForError(err error) {
+	p.mtx.Lock()
+	fmt.Println("Stopping ProxyApp for error:", err)
+	if p.err == nil {
+		p.err = err
+	}
+	p.mtx.Unlock()
+	p.Stop()
+}
+
+func (p *ProxyApp) Error() error {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+	return p.err
+}
+
+//----------------------------------------
+
+func (p *ProxyApp) sendRequestsRoutine() {
+	for {
+		var n int
+		var err error
+		select {
+		case <-p.QuitService.Quit:
+			return
+		case qreq := <-p.reqQueue:
+			wire.WriteBinary(qreq.Request, p.bufWriter, &n, &err)
+			if err != nil {
+				p.StopForError(err)
+				return
+			}
+			if _, ok := qreq.Request.(tmsp.RequestFlush); ok {
+				err = p.bufWriter.Flush()
+				if err != nil {
+					p.StopForError(err)
+					return
+				}
+			}
+			p.didSendReq(qreq)
+		}
+	}
+}
+
+func (p *ProxyApp) recvResponseRoutine() {
+	r := bufio.NewReader(p.conn) // Buffer reads
+	for {
+		var res tmsp.Response
+		var n int
+		var err error
+		wire.ReadBinaryPtr(&res, r, maxResponseSize, &n, &err)
+		if err != nil {
+			p.StopForError(err)
+			return
+		}
+		switch res := res.(type) {
+		case tmsp.ResponseException:
+			p.StopForError(errors.New(res.Error))
+		case tmsp.ResponseEvent:
+			p.didRecvEvent(res.Event)
+		default:
+			err := p.didRecvResponse(res)
+			if err != nil {
+				p.StopForError(err)
+			}
+		}
+	}
+}
+
+func (p *ProxyApp) didSendReq(qreq QueuedRequest) {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+
+	p.reqSent.PushBack(qreq)
+	if p.reqPending == nil {
+		p.reqPending = p.reqSent.Front()
+	}
+}
+
+func (p *ProxyApp) didRecvResponse(res tmsp.Response) error {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+
+	if p.reqPending == nil {
+		return fmt.Errorf("Unexpected result type %v when nothing expected",
+			reflect.TypeOf(res))
+	} else {
+		qreq := p.reqPending.Value.(QueuedRequest)
+		if !resMatchesReq(qreq.Request, res) {
+			return fmt.Errorf("Unexpected result type %v when response to %v expected",
+				reflect.TypeOf(res), reflect.TypeOf(qreq.Request))
+		}
+		if qreq.Sync {
+			qreq.Done()
+		}
+		p.reqPending = p.reqPending.Next()
+	}
+	p.resReceived.PushBack(res)
+	return nil
+}
+
+func (p *ProxyApp) didRecvEvent(event tmsp.Event) {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+
+	p.eventsReceived.PushBack(event)
+}
+
+//----------------------------------------
+
+func (p *ProxyApp) EchoAsync(key string) {
+	p.queueRequestAsync(tmsp.RequestEcho{key})
+}
+
+func (p *ProxyApp) FlushAsync() {
+	p.queueRequestAsync(tmsp.RequestFlush{})
+}
+
+func (p *ProxyApp) AppendTxAsync(tx []byte) {
+	p.queueRequestAsync(tmsp.RequestAppendTx{tx})
+}
+
+func (p *ProxyApp) GetHashAsync() {
+	p.queueRequestAsync(tmsp.RequestGetHash{})
+}
+
+/*
+func (p *ProxyApp) CommitAsync() {
+	p.queueRequestAsync(tmsp.RequestCommit{})
+}
+
+func (p *ProxyApp) RollbackAsync() {
+	p.queueRequestAsync(tmsp.RequestRollback{})
+}
+*/
+
+func (p *ProxyApp) SetEventsModeAsync(mode tmsp.EventsMode) {
+	p.queueRequestAsync(tmsp.RequestSetEventsMode{mode})
+}
+
+func (p *ProxyApp) AddListenerAsync(key string) {
+	p.queueRequestAsync(tmsp.RequestAddListener{key})
+}
+
+func (p *ProxyApp) RemListenerAsync(key string) {
+	p.queueRequestAsync(tmsp.RequestRemListener{key})
+}
+
+//----------------------------------------
+
+// Get valid txs, root hash, events; or error
+// Clears internal buffers
+func (p *ProxyApp) ReapSync(commit bool) (txs [][]byte, hash []byte, events []tmsp.Event, err error) {
+	if commit {
+		// Send asynchronous commit
+		p.queueRequestAsync(tmsp.RequestCommit{})
+		// NOTE: we're assuming that there won't be a race condition.
+	}
+	// Get hash.
+	p.queueRequestAsync(tmsp.RequestGetHash{})
+	// Flush everything.
+	p.queueRequestSync(tmsp.RequestFlush{})
+	// Maybe there was an error in response matching
+	if p.err != nil {
+		return nil, nil, nil, p.err
+	}
+	// Process the resReceived/reqSent/reqPending.
+	if p.resReceived.Len() != p.reqSent.Len() {
+		PanicSanity("Unmatched requests & responses")
+	}
+	var commitCounter = 0
+	txs = make([][]byte, 0, p.reqSent.Len())
+	events = make([]tmsp.Event, 0, p.eventsReceived.Len())
+	reqE, resE := p.reqSent.Front(), p.resReceived.Front()
+	for ; reqE != nil; reqE, resE = reqE.Next(), resE.Next() {
+		req, res := reqE.Value.(tmsp.Request), resE.Value.(tmsp.Response)
+		switch req := req.(type) {
+		case tmsp.RequestAppendTx:
+			txs = append(txs, req.TxBytes)
+		case tmsp.RequestGetHash:
+			hash = res.(tmsp.ResponseGetHash).Hash
+		case tmsp.RequestCommit:
+			if commitCounter > 0 {
+				PanicSanity("Unexpected Commit response")
+			}
+			commitCounter++
+		case tmsp.RequestRollback:
+			PanicSanity("Unexpected Rollback response")
+		default:
+			// ignore other messages
+		}
+	}
+	for eE := p.eventsReceived.Front(); eE != nil; eE = eE.Next() {
+		events = append(events, eE.Value.(tmsp.Event))
+	}
+
+	return txs, hash, events, nil
+}
+
+// Rollback or error
+// Clears internal buffers
+func (p *ProxyApp) RollbackSync() (err error) {
+	// Get hash.
+	p.queueRequestAsync(tmsp.RequestRollback{})
+	// Flush everything.
+	p.queueRequestSync(tmsp.RequestFlush{})
+	// Maybe there was an error in response matching
+	if p.err != nil {
+		return p.err
+	}
+	p.reqSent = list.New()
+	p.reqPending = nil
+	p.resReceived = list.New()
+	p.eventsReceived = list.New()
+	return nil
+}
+
+func (p *ProxyApp) InfoSync() []string {
+	p.queueRequestAsync(tmsp.RequestInfo{})
+	p.queueRequestSync(tmsp.RequestFlush{})
+	return p.resReceived.Back().Prev().Value.(tmsp.ResponseInfo).Data
+}
+
+func (p *ProxyApp) FlushSync() {
+	p.queueRequestSync(tmsp.RequestFlush{})
+}
+
+//----------------------------------------
+
+func (p *ProxyApp) queueRequestAsync(req tmsp.Request) {
+	qreq := QueuedRequest{Request: req}
+	p.reqQueue <- qreq
+}
+
+func (p *ProxyApp) queueRequestSync(req tmsp.Request) {
+	qreq := QueuedRequest{
+		req,
+		true,
+		waitGroup1(),
+	}
+	p.reqQueue <- qreq
+	qreq.Wait()
+}
+
+//----------------------------------------
+
+func waitGroup1() (wg *sync.WaitGroup) {
+	wg = &sync.WaitGroup{}
+	wg.Add(1)
+	return
+}
+
+func resMatchesReq(req tmsp.Request, res tmsp.Response) (ok bool) {
+	switch req.(type) {
+	case tmsp.RequestEcho:
+		_, ok = res.(tmsp.ResponseEcho)
+	case tmsp.RequestFlush:
+		_, ok = res.(tmsp.ResponseFlush)
+	case tmsp.RequestInfo:
+		_, ok = res.(tmsp.ResponseInfo)
+	case tmsp.RequestAppendTx:
+		_, ok = res.(tmsp.ResponseAppendTx)
+	case tmsp.RequestGetHash:
+		_, ok = res.(tmsp.ResponseGetHash)
+	case tmsp.RequestCommit:
+		_, ok = res.(tmsp.ResponseCommit)
+	case tmsp.RequestRollback:
+		_, ok = res.(tmsp.ResponseRollback)
+	case tmsp.RequestSetEventsMode:
+		_, ok = res.(tmsp.ResponseSetEventsMode)
+	case tmsp.RequestAddListener:
+		_, ok = res.(tmsp.ResponseAddListener)
+	case tmsp.RequestRemListener:
+		_, ok = res.(tmsp.ResponseRemListener)
+	default:
+		return false
+	}
+	return
+}
+
+type QueuedRequest struct {
+	tmsp.Request
+	Sync bool
+	*sync.WaitGroup
+}
diff --git a/proxy/proxy_app_test.go b/proxy/proxy_app_test.go
new file mode 100644
index 000000000..c387bbbba
--- /dev/null
+++ b/proxy/proxy_app_test.go
@@ -0,0 +1,101 @@
+package proxy
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	. "github.com/tendermint/go-common"
+	"github.com/tendermint/go-logio"
+	example "github.com/tendermint/tmsp/example"
+	"github.com/tendermint/tmsp/server"
+)
+
+func TestEcho(t *testing.T) {
+	sockPath := Fmt("unix:///tmp/echo_%v.sock", RandStr(6))
+	_, err := server.StartListener(sockPath, example.NewDummyApplication())
+	if err != nil {
+		Exit(err.Error())
+	}
+	conn, err := Connect(sockPath)
+	if err != nil {
+		Exit(err.Error())
+	} else {
+		t.Log("Connected")
+	}
+
+	logBuffer := bytes.NewBuffer(nil)
+	logConn := logio.NewLoggedConn(conn, logBuffer)
+	proxy := NewProxyApp(logConn, 10)
+	proxy.Start()
+
+	for i := 0; i < 1000; i++ {
+		proxy.EchoAsync(Fmt("echo-%v", i))
+	}
+	proxy.FlushSync()
+
+	if proxy.reqSent.Len() != 1001 {
+		t.Error(Fmt("Expected 1001 requests sent, got %v",
+			proxy.reqSent.Len()))
+	}
+	if proxy.resReceived.Len() != 1001 {
+		t.Error(Fmt("Expected 1001 responses received, got %v",
+			proxy.resReceived.Len()))
+	}
+	if t.Failed() {
+		logio.PrintReader(logBuffer)
+	}
+}
+
+func BenchmarkEcho(b *testing.B) {
+	b.StopTimer() // Initialize
+	sockPath := Fmt("unix:///tmp/echo_%v.sock", RandStr(6))
+	_, err := server.StartListener(sockPath, example.NewDummyApplication())
+	if err != nil {
+		Exit(err.Error())
+	}
+	conn, err := Connect(sockPath)
+	if err != nil {
+		Exit(err.Error())
+	} else {
+		b.Log("Connected")
+	}
+
+	proxy := NewProxyApp(conn, 10)
+	proxy.Start()
+	echoString := strings.Repeat(" ", 200)
+	b.StartTimer() // Start benchmarking tests
+
+	for i := 0; i < b.N; i++ {
+		proxy.EchoAsync(echoString)
+	}
+	proxy.FlushSync()
+
+	b.StopTimer()
+	// info := proxy.InfoSync()
+	//b.Log("N: ", b.N, info)
+}
+
+func TestInfo(t *testing.T) {
+	sockPath := Fmt("unix:///tmp/echo_%v.sock", RandStr(6))
+	_, err := server.StartListener(sockPath, example.NewDummyApplication())
+	if err != nil {
+		Exit(err.Error())
+	}
+	conn, err := Connect(sockPath)
+	if err != nil {
+		Exit(err.Error())
+	} else {
+		t.Log("Connected")
+	}
+
+	logBuffer := bytes.NewBuffer(nil)
+	logConn := logio.NewLoggedConn(conn, logBuffer)
+	proxy := NewProxyApp(logConn, 10)
+	proxy.Start()
+	data := proxy.InfoSync()
+
+	if data[0] != "size:0" {
+		t.Error("Expected ResponseInfo with one element 'size:0' but got something else")
+	}
+}