diff --git a/runner/go.mod b/runner/go.mod
index b666aea..2c0daec 100644
--- a/runner/go.mod
+++ b/runner/go.mod
@@ -2,9 +2,13 @@ module github.com/benchttp/desktop/runner
 
 go 1.17
 
-require github.com/benchttp/engine v0.1.1
+require (
+	github.com/benchttp/sdk v0.1.1
+)
 
 require (
 	golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
+
+replace github.com/benchttp/sdk => ../../engine
diff --git a/runner/httpclient/handle.go b/runner/httpclient/handle.go
index bdc0f7a..eb5e1df 100644
--- a/runner/httpclient/handle.go
+++ b/runner/httpclient/handle.go
@@ -2,13 +2,12 @@ package httpclient
 
 import (
 	"errors"
-	"io"
 	"log"
 	"net/http"
 	"time"
 
-	"github.com/benchttp/engine/configparse"
-	"github.com/benchttp/engine/runner"
+	"github.com/benchttp/sdk/benchttp"
+	"github.com/benchttp/sdk/configio"
 
 	"github.com/benchttp/desktop/runner/httpclient/response"
 )
@@ -16,28 +15,24 @@ import (
 func handle(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Access-Control-Allow-Origin", "*")
 
-	b, err := io.ReadAll(r.Body)
-	if err != nil {
-		internalError(w, err)
-		return
-	}
+	runner := benchttp.DefaultRunner()
+	runner.OnProgress = streamProgress(w)
 
-	cfg, err := configparse.JSON(b)
-	if err != nil {
+	if err := configio.NewJSONDecoder(r.Body).DecodeRunner(&runner); err != nil {
 		clientError(w, err)
 		return
 	}
 
-	rep, err := runner.New(streamProgress(w)).Run(r.Context(), cfg)
-	var invalidConfigError *runner.InvalidConfigError
+	report, err := runner.Run(r.Context())
+	var errInvalidRunner *benchttp.InvalidRunnerError
 	switch {
 	case err == nil:
 		// Pass through.
-	case err == runner.ErrCanceled:
+	case err == benchttp.ErrCanceled:
 		clientError(w, err)
 		return
-	case errors.As(err, &invalidConfigError):
-		clientError(w, invalidConfigError.Errors...)
+	case errors.As(err, &errInvalidRunner):
+		clientError(w, errInvalidRunner.Errors...)
 		return
 	default:
 		internalError(w, err)
@@ -49,14 +44,14 @@ func handle(w http.ResponseWriter, r *http.Request) {
 	// The issue is likely on the read side (front-end), but this is
 	// the easiest fix for now.
 	time.Sleep(10 * time.Millisecond)
-	if err := response.Report(rep).EncodeJSON(w); err != nil {
+	if err := response.Report(report).EncodeJSON(w); err != nil {
 		internalError(w, err)
 		return
 	}
 }
 
-func streamProgress(w http.ResponseWriter) func(runner.RecordingProgress) {
-	return func(progress runner.RecordingProgress) {
+func streamProgress(w http.ResponseWriter) func(benchttp.RecordingProgress) {
+	return func(progress benchttp.RecordingProgress) {
 		if err := response.Progress(progress).EncodeJSON(w); err != nil {
 			internalError(w, err)
 		}
diff --git a/runner/httpclient/response/progress.go b/runner/httpclient/response/progress.go
index 7a3674b..be93ab5 100644
--- a/runner/httpclient/response/progress.go
+++ b/runner/httpclient/response/progress.go
@@ -3,10 +3,10 @@ package response
 import (
 	"time"
 
-	"github.com/benchttp/engine/runner"
+	"github.com/benchttp/sdk/benchttp"
 )
 
-func Progress(in runner.RecordingProgress) Response {
+func Progress(in benchttp.RecordingProgress) Response {
 	return newResponse(progressResponse{
 		Done:      in.Done,
 		Error:     in.Error,
diff --git a/runner/httpclient/response/report.go b/runner/httpclient/response/report.go
index c4ba4aa..52a4c33 100644
--- a/runner/httpclient/response/report.go
+++ b/runner/httpclient/response/report.go
@@ -3,10 +3,10 @@ package response
 import (
 	"time"
 
-	"github.com/benchttp/engine/runner"
+	"github.com/benchttp/sdk/benchttp"
 )
 
-func Report(rep *runner.Report) Response {
+func Report(rep *benchttp.Report) Response {
 	return newResponse(reportResponse{
 		Metadata: metadataResponse{
 			FinishedAt:    rep.Metadata.FinishedAt,
@@ -87,7 +87,7 @@ type requestFailureResponse struct {
 	Reason string `json:"reason"`
 }
 
-func toTestResultsResponse(testResults []runner.TestCaseResult) []testResultResponse {
+func toTestResultsResponse(testResults []benchttp.TestCaseResult) []testResultResponse {
 	resp := make([]testResultResponse, len(testResults))
 	for i, r := range testResults {
 		resp[i] = testResultResponse{
@@ -104,7 +104,7 @@ func toTestResultsResponse(testResults []runner.TestCaseResult) []testResultResp
 	return resp
 }
 
-func toTimeStatsResponse(stats runner.MetricsTimeStats) timeStatsResponse {
+func toTimeStatsResponse(stats benchttp.MetricsTimeStats) timeStatsResponse {
 	return timeStatsResponse{
 		Min:       stats.Min,
 		Max:       stats.Max,
@@ -116,7 +116,7 @@ func toTimeStatsResponse(stats runner.MetricsTimeStats) timeStatsResponse {
 	}
 }
 
-func toRequestEventTimesResponse(in map[string]runner.MetricsTimeStats) map[string]timeStatsResponse {
+func toRequestEventTimesResponse(in map[string]benchttp.MetricsTimeStats) map[string]timeStatsResponse {
 	resp := map[string]timeStatsResponse{}
 	for k, v := range in {
 		resp[k] = toTimeStatsResponse(v)