diff --git a/relay/client/client_test.go b/relay/client/client_test.go
index b9068ccd9..42cd5bc67 100644
--- a/relay/client/client_test.go
+++ b/relay/client/client_test.go
@@ -2,8 +2,11 @@ package client
 
 import (
 	"context"
+	"crypto/rand"
+	"fmt"
 	"net"
 	"os"
+	"sync"
 	"testing"
 	"time"
 
@@ -108,6 +111,122 @@ func TestClient(t *testing.T) {
 	}
 }
 
+func TestDataTransfer(t *testing.T) {
+	ctx := context.Background()
+
+	testData, err := seedRandomData()
+	if err != nil {
+		t.Fatalf("failed to seed random data: %s", err)
+	}
+
+	srv := server.NewServer(serverURL, false, av)
+	errChan := make(chan error, 1)
+	go func() {
+		listenCfg := server.ListenerConfig{Address: serverListenAddr}
+		err := srv.Listen(listenCfg)
+		if err != nil {
+			errChan <- err
+		}
+	}()
+
+	defer func() {
+		err := srv.Close()
+		if err != nil {
+			t.Errorf("failed to close server: %s", err)
+		}
+	}()
+
+	// wait for server to start
+	if err := waitForServerToStart(errChan); err != nil {
+		t.Fatalf("failed to start server: %s", err)
+	}
+
+	peerPairs := 50
+	clientsSender := make([]*Client, peerPairs)
+	for i := 0; i < cap(clientsSender); i++ {
+		c := NewClient(ctx, serverURL, hmacTokenStore, "sender-"+fmt.Sprint(i))
+		err := c.Connect()
+		if err != nil {
+			t.Fatalf("failed to connect to server: %s", err)
+		}
+		clientsSender[i] = c
+	}
+
+	clientsReceiver := make([]*Client, peerPairs)
+	for i := 0; i < cap(clientsSender); i++ {
+		c := NewClient(ctx, serverURL, hmacTokenStore, "receiver-"+fmt.Sprint(i))
+		err := c.Connect()
+		if err != nil {
+			t.Fatalf("failed to connect to server: %s", err)
+		}
+		clientsReceiver[i] = c
+	}
+
+	connsSender := make([]net.Conn, 0, peerPairs)
+	connsReceiver := make([]net.Conn, 0, peerPairs)
+	for i := 0; i < len(clientsSender); i++ {
+		conn, err := clientsSender[i].OpenConn("receiver-" + fmt.Sprint(i))
+		if err != nil {
+			t.Fatalf("failed to bind channel: %s", err)
+		}
+		connsSender = append(connsSender, conn)
+
+		conn, err = clientsReceiver[i].OpenConn("sender-" + fmt.Sprint(i))
+		if err != nil {
+			t.Fatalf("failed to bind channel: %s", err)
+		}
+		connsReceiver = append(connsReceiver, conn)
+	}
+
+	wg := sync.WaitGroup{}
+	for i := 0; i < len(connsSender); i++ {
+		wg.Add(2)
+		go func(i int) {
+			pieceSize := 1024
+			testDataLen := len(testData)
+
+			for j := 0; j < testDataLen; j += pieceSize {
+				end := j + pieceSize
+				if end > testDataLen {
+					end = testDataLen
+				}
+				_, err := connsSender[i].Write(testData[j:end])
+				if err != nil {
+					t.Fatalf("failed to write to channel: %s", err)
+				}
+			}
+			wg.Done()
+		}(i)
+
+		go func(i int) {
+			for receivedSize := 0; receivedSize < len(testData); {
+				buf := make([]byte, 8192)
+				n, err := connsReceiver[i].Read(buf)
+				if err != nil {
+					t.Fatalf("failed to read from channel: %s", err)
+				}
+
+				receivedSize += n
+			}
+			wg.Done()
+		}(i)
+	}
+
+	wg.Wait()
+
+	for i := 0; i < len(connsSender); i++ {
+		err := connsSender[i].Close()
+		if err != nil {
+			t.Errorf("failed to close connection: %s", err)
+		}
+
+		err = connsReceiver[i].Close()
+		if err != nil {
+			t.Errorf("failed to close connection: %s", err)
+		}
+	}
+}
+
 func TestRegistration(t *testing.T) {
 	ctx := context.Background()
 	srvCfg := server.ListenerConfig{Address: serverListenAddr}
@@ -601,3 +720,12 @@ func waitForServerToStart(errChan chan error) error {
 	}
 	return nil
 }
+
+func seedRandomData() ([]byte, error) {
+	token := make([]byte, 1024*1024*10)
+	_, err := rand.Read(token)
+	if err != nil {
+		return nil, err
+	}
+	return token, nil
+}