diff --git a/testsuite/devserver.go b/testsuite/devserver.go
new file mode 100644
index 000000000..f8f33d9c9
--- /dev/null
+++ b/testsuite/devserver.go
@@ -0,0 +1,368 @@
+// The MIT License
+//
+// Copyright (c) 2022 Temporal Technologies Inc.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package testsuite
+
+import (
+	"archive/tar"
+	"archive/zip"
+	"bytes"
+	"compress/gzip"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"syscall"
+	"time"
+
+	"go.temporal.io/sdk/client"
+	"go.temporal.io/sdk/internal"
+	ilog "go.temporal.io/sdk/internal/log"
+	"go.temporal.io/sdk/log"
+)
+
+// Cached download of the dev server.
+type CachedDownload struct {
+	// Which version to download, by default the latest version compatible with the SDK will be downloaded.
+	// Acceptable values are specific release versions (e.g v0.3.0), "default", and "latest".
+	Version string
+	// Destination directory or the user temp directory if unset.
+	DestDir string
+}
+
+// Configuration for the dev server.
+type DevServerOptions struct {
+	// Existing path on the filesystem for the executable.
+	ExistingPath string
+	// Download the executable if not already there.
+	CachedDownload CachedDownload
+	// Client options used to create a client for the dev server.
+	// The provided Namespace or the "default" namespace is automatically registered on startup.
+	// If HostPort is provided, the host and port will be used to bind the server, otherwise the server will bind to
+	// localhost and obtain a free port.
+	ClientOptions *client.Options
+	// SQLite DB filename if persisting or non-persistent if none.
+	DBFilename string
+	// Whether to enable the UI.
+	EnableUI bool
+	// Log format - defaults to "pretty".
+	LogFormat string
+	// Log level - defaults to "warn".
+	LogLevel string
+	// Additional arguments to the dev server.
+	ExtraArgs []string
+}
+
+// Temporal CLI based DevServer
+type DevServer struct {
+	cmd    *exec.Cmd
+	client client.Client
+}
+
+// StartDevServer starts a Temporal CLI dev server process. This may download the server if not already downloaded.
+func StartDevServer(ctx context.Context, options DevServerOptions) (*DevServer, error) {
+	clientOptions := options.clientOptionsOrDefault()
+
+	exePath, err := downloadIfNeeded(ctx, &options, clientOptions.Logger)
+	if err != nil {
+		return nil, err
+	}
+
+	if clientOptions.HostPort == "" {
+		// Make sure this is done after downloading to reduce the chance (however slim) that the free port would be used
+		// up by the time the download completes.
+		clientOptions.HostPort, err = getFreeHostPort()
+		if err != nil {
+			return nil, err
+		}
+	}
+	host, port, err := net.SplitHostPort(clientOptions.HostPort)
+	if err != nil {
+		return nil, fmt.Errorf("invalid HostPort: %w", err)
+	}
+
+	args := prepareCommand(&options, host, port, clientOptions.Namespace)
+	cmd := exec.Command(exePath, args...)
+	cmd.Stdout, cmd.Stderr = os.Stdout, os.Stderr
+	clientOptions.Logger.Info("Starting DevServer", "ExePath", exePath, "Args", args)
+	if err := cmd.Start(); err != nil {
+		return nil, fmt.Errorf("failed starting: %w", err)
+	}
+
+	returnedClient, err := waitServerReady(ctx, clientOptions)
+	if err != nil {
+		return nil, err
+	}
+	clientOptions.Logger.Info("DevServer ready")
+	return &DevServer{client: returnedClient, cmd: cmd}, nil
+}
+
+func prepareCommand(options *DevServerOptions, host, port, namespace string) []string {
+	args := []string{
+		"server",
+		"start-dev",
+		"--ip", host, "--port", port,
+		"--namespace", namespace,
+		"--dynamic-config-value", "frontend.enableServerVersionCheck=false",
+	}
+	if options.LogLevel != "" {
+		args = append(args, "--log-level", options.LogLevel)
+	}
+	if options.LogFormat != "" {
+		args = append(args, "--log-format", options.LogFormat)
+	}
+	if !options.EnableUI {
+		args = append(args, "--headless")
+	}
+	if options.DBFilename != "" {
+		args = append(args, "--db-filename", options.DBFilename)
+	}
+	return append(args, options.ExtraArgs...)
+}
+
+func downloadIfNeeded(ctx context.Context, options *DevServerOptions, logger log.Logger) (string, error) {
+	if options.ExistingPath != "" {
+		return options.ExistingPath, nil
+	}
+	version := options.CachedDownload.Version
+	if version == "" {
+		version = "default"
+	}
+	destDir := options.CachedDownload.DestDir
+	if destDir == "" {
+		destDir = os.TempDir()
+	}
+	var exePath string
+	// Build path based on version and check if already present
+	if version == "default" {
+		exePath = filepath.Join(destDir, "temporal-cli-go-sdk-"+internal.SDKVersion)
+	} else {
+		exePath = filepath.Join(destDir, "temporal-cli-"+version)
+	}
+	if runtime.GOOS == "windows" {
+		exePath += ".exe"
+	}
+	if _, err := os.Stat(exePath); err == nil {
+		return exePath, nil
+	}
+
+	client := &http.Client{}
+
+	// Build info URL
+	platform := runtime.GOOS
+	if platform != "windows" && platform != "darwin" && platform != "linux" {
+		return "", fmt.Errorf("unsupported platform %v", platform)
+	}
+	arch := runtime.GOARCH
+	if arch != "amd64" && arch != "arm64" {
+		return "", fmt.Errorf("unsupported architecture %v", arch)
+	}
+	infoURL := fmt.Sprintf("https://temporal.download/cli/%v?platform=%v&arch=%v&sdk-name=sdk-go&sdk-version=%v", url.QueryEscape(version), platform, arch, internal.SDKVersion)
+
+	// Get info
+	info := struct {
+		ArchiveURL    string `json:"archiveUrl"`
+		FileToExtract string `json:"fileToExtract"`
+	}{}
+	req, err := http.NewRequestWithContext(ctx, "GET", infoURL, nil)
+	if err != nil {
+		return "", fmt.Errorf("failed preparing request: %w", err)
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("failed fetching info: %w", err)
+	}
+	b, err := io.ReadAll(resp.Body)
+	if closeErr := resp.Body.Close(); closeErr != nil {
+		logger.Warn("Failed to close response body: %v", closeErr)
+	}
+	if err != nil {
+		return "", fmt.Errorf("failed fetching info body: %w", err)
+	} else if resp.StatusCode != 200 {
+		return "", fmt.Errorf("failed fetching info, status: %v, body: %s", resp.Status, b)
+	} else if err = json.Unmarshal(b, &info); err != nil {
+		return "", fmt.Errorf("failed unmarshaling info: %w", err)
+	}
+
+	// Download and extract
+	logger.Info("Downloading temporal CLI", "Url", info.ArchiveURL, "ExePath", exePath)
+	req, err = http.NewRequestWithContext(ctx, "GET", info.ArchiveURL, nil)
+	if err != nil {
+		return "", fmt.Errorf("failed preparing request: %w", err)
+	}
+	resp, err = client.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("failed downloading: %w", err)
+	}
+	defer func() {
+		if closeErr := resp.Body.Close(); closeErr != nil {
+			logger.Warn("Failed to close response body: %v", closeErr)
+		}
+	}()
+	if resp.StatusCode != 200 {
+		return "", fmt.Errorf("failed downloading, status: %v", resp.Status)
+	}
+	// We want to download to a temporary file then rename. A better system-wide
+	// atomic downloader would use a common temp file and check whether it exists
+	// and wait on it, but doing multiple downloads in racy situations is
+	// good/simple enough for now.
+	// Note that we don't use os.TempDir here, instead we use the user provided destination directory which is
+	// guaranteed to make the rename atomic.
+	f, err := os.CreateTemp(destDir, "temporal-cli-downloading-")
+	if err != nil {
+		return "", fmt.Errorf("failed creating temp file: %w", err)
+	}
+	if strings.HasSuffix(info.ArchiveURL, ".tar.gz") {
+		err = extractTarball(resp.Body, info.FileToExtract, f)
+	} else if strings.HasSuffix(info.ArchiveURL, ".zip") {
+		err = extractZip(resp.Body, info.FileToExtract, f)
+	} else {
+		err = fmt.Errorf("unrecognized file extension on %v", info.ArchiveURL)
+	}
+	closeErr := f.Close()
+	if err != nil {
+		return "", err
+	} else if closeErr != nil {
+		return "", fmt.Errorf("failed to close temp file: %w", closeErr)
+	}
+	// Chmod it if not Windows
+	if runtime.GOOS != "windows" {
+		if err := os.Chmod(f.Name(), 0755); err != nil {
+			return "", fmt.Errorf("failed chmod'ing file: %w", err)
+		}
+	}
+	if err = os.Rename(f.Name(), exePath); err != nil {
+		return "", fmt.Errorf("failed moving file: %w", err)
+	}
+	return exePath, nil
+}
+
+func (opts *DevServerOptions) clientOptionsOrDefault() client.Options {
+	var out client.Options
+	if opts.ClientOptions != nil {
+		// Shallow copy the client options since we intend to overwrite some fields.
+		out = *opts.ClientOptions
+	}
+	if out.Logger == nil {
+		out.Logger = ilog.NewDefaultLogger()
+	}
+	if out.Namespace == "" {
+		out.Namespace = "default"
+	}
+	return out
+}
+
+func extractTarball(r io.Reader, toExtract string, w io.Writer) error {
+	r, err := gzip.NewReader(r)
+	if err != nil {
+		return err
+	}
+	tarRead := tar.NewReader(r)
+	for {
+		h, err := tarRead.Next()
+		if err != nil {
+			// This can be EOF which means we never found our file
+			return err
+		} else if h.Name == toExtract {
+			_, err = io.Copy(w, tarRead)
+			return err
+		}
+	}
+}
+
+func extractZip(r io.Reader, toExtract string, w io.Writer) error {
+	// Instead of using a third party zip streamer, and since Go stdlib doesn't
+	// support streaming read, we'll just put the entire archive in memory for now
+	b, err := io.ReadAll(r)
+	if err != nil {
+		return err
+	}
+	zipRead, err := zip.NewReader(bytes.NewReader(b), int64(len(b)))
+	if err != nil {
+		return err
+	}
+	for _, file := range zipRead.File {
+		if file.Name == toExtract {
+			r, err := file.Open()
+			if err != nil {
+				return err
+			}
+			_, err = io.Copy(w, r)
+			return err
+		}
+	}
+	return fmt.Errorf("could not find file in zip archive")
+}
+
+// waitServerReady repeatedly attempts to dial the server with given options until it is ready or it is time to give up.
+// Returns a connected client created using the provided options.
+func waitServerReady(ctx context.Context, options client.Options) (client.Client, error) {
+	var returnedClient client.Client
+	lastErr := retryFor(600, 100*time.Millisecond, func() error {
+		var err error
+		returnedClient, err = client.Dial(options)
+		return err
+	})
+	if lastErr != nil {
+		return nil, fmt.Errorf("failed connecting after timeout, last error: %w", lastErr)
+	}
+	return returnedClient, lastErr
+}
+
+// retryFor retries some function until it returns nil or runs out of attempts. Wait interval between attempts.
+func retryFor(maxAttempts int, interval time.Duration, cond func() error) error {
+	if maxAttempts < 1 {
+		// this is used internally, okay to panic
+		panic("maxAttempts should be at least 1")
+	}
+	var lastErr error
+	for i := 0; i < maxAttempts; i++ {
+		if curE := cond(); curE == nil {
+			return nil
+		} else {
+			lastErr = curE
+		}
+		time.Sleep(interval)
+	}
+	return lastErr
+}
+
+// Stop the running server and wait for shutdown to complete. Error is propagated from server shutdown.
+func (s *DevServer) Stop() error {
+	if err := s.cmd.Process.Signal(syscall.SIGTERM); err != nil {
+		return err
+	}
+	return s.cmd.Wait()
+}
+
+// Get a connected client, configured to work with the dev server.
+func (s *DevServer) Client() client.Client {
+	return s.client
+}
diff --git a/testsuite/devserver_test.go b/testsuite/devserver_test.go
new file mode 100644
index 000000000..c25e8c868
--- /dev/null
+++ b/testsuite/devserver_test.go
@@ -0,0 +1,60 @@
+// The MIT License
+//
+// Copyright (c) 2022 Temporal Technologies Inc.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package testsuite_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.temporal.io/api/workflowservice/v1"
+	"go.temporal.io/sdk/client"
+	"go.temporal.io/sdk/testsuite"
+)
+
+func TestStartDevServer_Defaults(t *testing.T) {
+	server, err := testsuite.StartDevServer(context.Background(), testsuite.DevServerOptions{})
+	require.NoError(t, err)
+	defer require.NoError(t, server.Stop())
+	info, err := server.Client().WorkflowService().GetSystemInfo(context.Background(), &workflowservice.GetSystemInfoRequest{})
+	require.NoError(t, err)
+	require.NotNil(t, info.Capabilities)
+}
+
+func TestStartDevServer_SpecificVersion(t *testing.T) {
+	server, err := testsuite.StartDevServer(context.Background(), testsuite.DevServerOptions{CachedDownload: testsuite.CachedDownload{Version: "v0.3.0"}})
+	require.NoError(t, err)
+	defer require.NoError(t, server.Stop())
+	info, err := server.Client().WorkflowService().GetSystemInfo(context.Background(), &workflowservice.GetSystemInfoRequest{})
+	require.NoError(t, err)
+	require.NotNil(t, info.Capabilities)
+}
+
+func TestStartDevServer_CustomNamespace(t *testing.T) {
+	server, err := testsuite.StartDevServer(context.Background(), testsuite.DevServerOptions{ClientOptions: &client.Options{Namespace: "testing"}})
+	require.NoError(t, err)
+	defer require.NoError(t, server.Stop())
+	info, err := server.Client().WorkflowService().DescribeNamespace(context.Background(), &workflowservice.DescribeNamespaceRequest{Namespace: "testing"})
+	require.NoError(t, err)
+	require.Equal(t, "testing", info.NamespaceInfo.Name)
+}
diff --git a/testsuite/freeport.go b/testsuite/freeport.go
new file mode 100644
index 000000000..5dada2af6
--- /dev/null
+++ b/testsuite/freeport.go
@@ -0,0 +1,80 @@
+// The MIT License
+//
+// Copyright (c) 2022 Temporal Technologies Inc.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+package testsuite
+
+import (
+	"fmt"
+	"net"
+)
+
+// Modified from Temporalite which itself modified from
+// https://github.com/phayes/freeport/blob/95f893ade6f232a5f1511d61735d89b1ae2df543/freeport.go
+
+func newPortProvider() *portProvider {
+	return &portProvider{}
+}
+
+type portProvider struct {
+	listeners []*net.TCPListener
+}
+
+// GetFreePort asks the kernel for a free open port that is ready to use.
+// Returns the interface's IP and the free port.
+func (p *portProvider) GetFreePort() (string, int, error) {
+	addr, err := net.ResolveTCPAddr("tcp", "127.0.0.1:0")
+	if err != nil {
+		if addr, err = net.ResolveTCPAddr("tcp6", "[::1]:0"); err != nil {
+			return "", 0, fmt.Errorf("failed to get free port: %w", err)
+		}
+	}
+
+	l, err := net.ListenTCP("tcp", addr)
+	if err != nil {
+		return "", 0, err
+	}
+
+	p.listeners = append(p.listeners, l)
+	tcpAddr := l.Addr().(*net.TCPAddr)
+
+	return tcpAddr.IP.String(), tcpAddr.Port, nil
+}
+
+func (p *portProvider) Close() error {
+	for _, l := range p.listeners {
+		if err := l.Close(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func getFreeHostPort() (string, error) {
+	pp := newPortProvider()
+	host, port, err := pp.GetFreePort()
+	closeErr := pp.Close()
+	if err != nil {
+		return "", err
+	} else if closeErr != nil {
+		return "", fmt.Errorf("failed to close TCP listener: %w", closeErr)
+	}
+	return fmt.Sprintf("%v:%v", host, port), nil
+}
diff --git a/testsuite/testsuite.go b/testsuite/testsuite.go
index b13023347..eba27e666 100644
--- a/testsuite/testsuite.go
+++ b/testsuite/testsuite.go
@@ -22,7 +22,8 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.
 
-// Package testsuite contains unit testing framework for Temporal workflows and activities.
+// Package testsuite contains unit testing framework for Temporal workflows and activities and a helper to download and
+// start a dev server.
 package testsuite
 
 import (