diff --git a/benchttp/internal/metrics/aggregate.go b/benchttp/metrics/aggregate.go
similarity index 87%
rename from benchttp/internal/metrics/aggregate.go
rename to benchttp/metrics/aggregate.go
index e01788f..779b14d 100644
--- a/benchttp/internal/metrics/aggregate.go
+++ b/benchttp/metrics/aggregate.go
@@ -3,19 +3,16 @@ package metrics
 import (
 	"time"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics/timestats"
-	"github.com/benchttp/engine/benchttp/internal/recorder"
+	"github.com/benchttp/engine/benchttp/recorder"
 )
 
-type TimeStats = timestats.TimeStats
-
 // Aggregate is an aggregate of metrics computed from
 // a slice of recorder.Record.
 type Aggregate struct {
 	// ResponseTimes is the common statistics computed from a
 	// slice recorder.Record. It offers statistics about the
 	// recorder.Record.Time of the records.
-	ResponseTimes timestats.TimeStats
+	ResponseTimes TimeStats
 	// StatusCodesDistribution maps each status code received to
 	// its number of occurrence.
 	StatusCodesDistribution map[int]int
@@ -23,7 +20,7 @@ type Aggregate struct {
 	// the combination of all recorder.Record.Events of a slice
 	// of recorder.Record. It offers statistics about the
 	// recorder.Events.Time of the records.
-	RequestEventTimes map[string]timestats.TimeStats
+	RequestEventTimes map[string]TimeStats
 	// Records lists each response time received during the run.
 	// It offers raw informarion.
 	Records []struct {
@@ -51,7 +48,7 @@ func NewAggregate(records []recorder.Record) (agg Aggregate) {
 		}
 	}
 
-	agg.ResponseTimes = timestats.New(times)
+	agg.ResponseTimes = NewTimeStats(times)
 
 	agg.StatusCodesDistribution = computeStatusCodesDistribution(records)
 
@@ -77,7 +74,7 @@ func (agg Aggregate) RequestSuccessCount() int {
 
 // Special compute helpers.
 
-func computeRequestEventTimes(records []recorder.Record) map[string]timestats.TimeStats {
+func computeRequestEventTimes(records []recorder.Record) map[string]TimeStats {
 	events := flattenRelativeTimeEvents(records)
 
 	timesByEvent := map[string][]time.Duration{}
@@ -86,10 +83,10 @@ func computeRequestEventTimes(records []recorder.Record) map[string]timestats.Ti
 		timesByEvent[e.Name] = append(timesByEvent[e.Name], e.Time)
 	}
 
-	statsByEvent := map[string]timestats.TimeStats{}
+	statsByEvent := map[string]TimeStats{}
 
 	for e, times := range timesByEvent {
-		statsByEvent[e] = timestats.New(times)
+		statsByEvent[e] = NewTimeStats(times)
 	}
 
 	return statsByEvent
diff --git a/benchttp/internal/metrics/aggregate_test.go b/benchttp/metrics/aggregate_test.go
similarity index 87%
rename from benchttp/internal/metrics/aggregate_test.go
rename to benchttp/metrics/aggregate_test.go
index b8a2251..1d0d4d7 100644
--- a/benchttp/internal/metrics/aggregate_test.go
+++ b/benchttp/metrics/aggregate_test.go
@@ -5,14 +5,13 @@ import (
 	"testing"
 	"time"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics"
-	"github.com/benchttp/engine/benchttp/internal/metrics/timestats"
-	"github.com/benchttp/engine/benchttp/internal/recorder"
+	"github.com/benchttp/engine/benchttp/metrics"
+	"github.com/benchttp/engine/benchttp/recorder"
 )
 
 func TestNewAggregate(t *testing.T) {
-	// Test for "response times stats" is delegated to timestats.New because
-	// metrics.NewAggregate does not have any specific behavior aound it.
+	// Test for "response times stats" is delegated to metrics.NewTimeStats
+	// because metrics.NewAggregate does not have any specific behavior aound it.
 
 	t.Run("events times stats", func(t *testing.T) {
 		eventsStub := func(t1, t2 time.Duration) []recorder.Event {
@@ -26,7 +25,7 @@ func TestNewAggregate(t *testing.T) {
 			{Events: eventsStub(400, 500)},
 		}
 
-		want := map[string]timestats.TimeStats{
+		want := map[string]metrics.TimeStats{
 			"1": {Min: 100, Max: 400, Mean: 250, Median: 250},
 			"2": {Min: 200, Max: 500, Mean: 325, Median: 300},
 		}
diff --git a/benchttp/internal/metrics/compare.go b/benchttp/metrics/compare.go
similarity index 100%
rename from benchttp/internal/metrics/compare.go
rename to benchttp/metrics/compare.go
diff --git a/benchttp/internal/metrics/field.go b/benchttp/metrics/field.go
similarity index 100%
rename from benchttp/internal/metrics/field.go
rename to benchttp/metrics/field.go
diff --git a/benchttp/internal/metrics/field_test.go b/benchttp/metrics/field_test.go
similarity index 96%
rename from benchttp/internal/metrics/field_test.go
rename to benchttp/metrics/field_test.go
index fb430ae..19f4003 100644
--- a/benchttp/internal/metrics/field_test.go
+++ b/benchttp/metrics/field_test.go
@@ -3,7 +3,7 @@ package metrics_test
 import (
 	"testing"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics"
+	"github.com/benchttp/engine/benchttp/metrics"
 )
 
 func TestField_Type(t *testing.T) {
diff --git a/benchttp/internal/metrics/metrics.go b/benchttp/metrics/metrics.go
similarity index 97%
rename from benchttp/internal/metrics/metrics.go
rename to benchttp/metrics/metrics.go
index 0f3abe7..d280d12 100644
--- a/benchttp/internal/metrics/metrics.go
+++ b/benchttp/metrics/metrics.go
@@ -3,7 +3,7 @@ package metrics
 import (
 	"strings"
 
-	"github.com/benchttp/engine/benchttp/internal/reflectpath"
+	"github.com/benchttp/engine/internal/reflectpath"
 )
 
 // Value is a concrete metric value, e.g. 120 or 3 * time.Second.
diff --git a/benchttp/internal/metrics/metrics_test.go b/benchttp/metrics/metrics_test.go
similarity index 93%
rename from benchttp/internal/metrics/metrics_test.go
rename to benchttp/metrics/metrics_test.go
index dd2c983..f89faee 100644
--- a/benchttp/internal/metrics/metrics_test.go
+++ b/benchttp/metrics/metrics_test.go
@@ -4,8 +4,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics"
-	"github.com/benchttp/engine/benchttp/internal/metrics/timestats"
+	"github.com/benchttp/engine/benchttp/metrics"
 )
 
 func TestMetric_Compare(t *testing.T) {
@@ -87,7 +86,7 @@ func TestAggregate_MetricOf(t *testing.T) {
 			name:    "get metrics from nested struct",
 			fieldID: "ResponseTimes.Mean",
 			agg: metrics.Aggregate{
-				ResponseTimes: timestats.TimeStats{
+				ResponseTimes: metrics.TimeStats{
 					Mean: 100 * time.Millisecond,
 				},
 			},
@@ -114,7 +113,7 @@ func TestAggregate_MetricOf(t *testing.T) {
 			name:    "get metrics from string map",
 			fieldID: "RequestEventTimes.FirstResponseByte.Mean",
 			agg: metrics.Aggregate{
-				RequestEventTimes: map[string]timestats.TimeStats{
+				RequestEventTimes: map[string]metrics.TimeStats{
 					"FirstResponseByte": {Mean: 100 * time.Millisecond},
 				},
 			},
@@ -132,7 +131,7 @@ func TestAggregate_MetricOf(t *testing.T) {
 			name:    "case insensitive",
 			fieldID: "responsetimes.MEAN",
 			agg: metrics.Aggregate{
-				ResponseTimes: timestats.TimeStats{
+				ResponseTimes: metrics.TimeStats{
 					Mean: 100 * time.Millisecond,
 				},
 			},
diff --git a/benchttp/internal/metrics/timestats/timestats.go b/benchttp/metrics/timestats.go
similarity index 96%
rename from benchttp/internal/metrics/timestats/timestats.go
rename to benchttp/metrics/timestats.go
index ea3f883..d00b6c2 100644
--- a/benchttp/internal/metrics/timestats/timestats.go
+++ b/benchttp/metrics/timestats.go
@@ -1,4 +1,4 @@
-package timestats
+package metrics
 
 import (
 	"math"
@@ -17,7 +17,7 @@ type TimeStats struct {
 	Deciles                        []time.Duration
 }
 
-func New(times []time.Duration) TimeStats {
+func NewTimeStats(times []time.Duration) TimeStats {
 	n := len(times)
 	if n == 0 {
 		return TimeStats{}
diff --git a/benchttp/internal/metrics/timestats/sort.go b/benchttp/metrics/timestats_sort.go
similarity index 94%
rename from benchttp/internal/metrics/timestats/sort.go
rename to benchttp/metrics/timestats_sort.go
index 391cbf8..c7d97b4 100644
--- a/benchttp/internal/metrics/timestats/sort.go
+++ b/benchttp/metrics/timestats_sort.go
@@ -1,4 +1,4 @@
-package timestats
+package metrics
 
 import (
 	"time"
diff --git a/benchttp/internal/metrics/timestats/timestats_test.go b/benchttp/metrics/timestats_test.go
similarity index 83%
rename from benchttp/internal/metrics/timestats/timestats_test.go
rename to benchttp/metrics/timestats_test.go
index 522208a..de2fad7 100644
--- a/benchttp/internal/metrics/timestats/timestats_test.go
+++ b/benchttp/metrics/timestats_test.go
@@ -1,15 +1,15 @@
-package timestats_test
+package metrics_test
 
 import (
 	"testing"
 	"time"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics/timestats"
+	"github.com/benchttp/engine/benchttp/metrics"
 )
 
 func TestCompute(t *testing.T) {
 	t.Run("happy path", func(t *testing.T) {
-		want := timestats.TimeStats{
+		want := metrics.TimeStats{
 			Min:       100,
 			Max:       400,
 			Mean:      230,
@@ -21,7 +21,7 @@ func TestCompute(t *testing.T) {
 
 		data := []time.Duration{100, 100, 200, 300, 400, 200, 100, 200, 300, 400, 100, 100, 200, 300, 400, 200, 100, 200, 300, 400}
 
-		got := timestats.New(data)
+		got := metrics.NewTimeStats(data)
 
 		for _, stat := range []struct {
 			name string
@@ -62,7 +62,7 @@ func TestCompute(t *testing.T) {
 
 	t.Run("few values", func(t *testing.T) {
 		data := []time.Duration{100, 300}
-		got := timestats.New(data)
+		got := metrics.NewTimeStats(data)
 
 		if got.Deciles != nil {
 			t.Errorf("deciles: want nil, got %v", got.Deciles)
@@ -77,8 +77,3 @@ func TestCompute(t *testing.T) {
 		}
 	})
 }
-
-// approxEqual returns true if val is equal to target with a margin of error.
-func approxEqualTime(val, target, margin time.Duration) bool {
-	return val >= target-margin && val <= target+margin
-}
diff --git a/benchttp/internal/recorder/error.go b/benchttp/recorder/error.go
similarity index 100%
rename from benchttp/internal/recorder/error.go
rename to benchttp/recorder/error.go
diff --git a/benchttp/internal/recorder/httputil.go b/benchttp/recorder/httputil.go
similarity index 100%
rename from benchttp/internal/recorder/httputil.go
rename to benchttp/recorder/httputil.go
diff --git a/benchttp/internal/recorder/progress.go b/benchttp/recorder/progress.go
similarity index 100%
rename from benchttp/internal/recorder/progress.go
rename to benchttp/recorder/progress.go
diff --git a/benchttp/internal/recorder/recorder.go b/benchttp/recorder/recorder.go
similarity index 98%
rename from benchttp/internal/recorder/recorder.go
rename to benchttp/recorder/recorder.go
index 1e9be56..1bbd139 100644
--- a/benchttp/internal/recorder/recorder.go
+++ b/benchttp/recorder/recorder.go
@@ -7,7 +7,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/benchttp/engine/internal/dispatcher"
+	"github.com/benchttp/engine/internal/workerpool"
 )
 
 const (
@@ -91,7 +91,7 @@ func (r *Recorder) Record(ctx context.Context, req *http.Request) ([]Record, err
 	r.start = time.Now()
 	go r.tickProgress()
 
-	err := dispatcher.
+	err := workerpool.
 		New(numWorker).
 		Do(ctx, maxIter, r.recordSingle(req, interval))
 
diff --git a/benchttp/internal/recorder/recorder_internal_test.go b/benchttp/recorder/recorder_internal_test.go
similarity index 97%
rename from benchttp/internal/recorder/recorder_internal_test.go
rename to benchttp/recorder/recorder_internal_test.go
index bc79fe8..162e4c4 100644
--- a/benchttp/internal/recorder/recorder_internal_test.go
+++ b/benchttp/recorder/recorder_internal_test.go
@@ -9,7 +9,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/benchttp/engine/internal/dispatcher"
+	"github.com/benchttp/engine/internal/workerpool"
 )
 
 var errTest = errors.New("test-generated error")
@@ -32,7 +32,7 @@ func TestRecorder_Run(t *testing.T) {
 			exp: ErrConnection,
 		},
 		{
-			label: "return dispatcher.ErrInvalidValue early on bad dispatcher value",
+			label: "return workerpool.ErrInvalidValue early on bad workerpool value",
 			req: withNoopTransport(New(Config{
 				Requests:       1,
 				Concurrency:    2, // bad: Concurrency > Requests
@@ -40,7 +40,7 @@ func TestRecorder_Run(t *testing.T) {
 				GlobalTimeout:  3 * time.Second,
 			},
 			)),
-			exp: dispatcher.ErrInvalidValue,
+			exp: workerpool.ErrInvalidValue,
 		},
 	}
 
diff --git a/benchttp/internal/recorder/tracer.go b/benchttp/recorder/tracer.go
similarity index 100%
rename from benchttp/internal/recorder/tracer.go
rename to benchttp/recorder/tracer.go
diff --git a/benchttp/internal/recorder/tracer_internal_test.go b/benchttp/recorder/tracer_internal_test.go
similarity index 100%
rename from benchttp/internal/recorder/tracer_internal_test.go
rename to benchttp/recorder/tracer_internal_test.go
diff --git a/benchttp/report.go b/benchttp/report.go
index 08b2589..9b9cda5 100644
--- a/benchttp/report.go
+++ b/benchttp/report.go
@@ -3,15 +3,15 @@ package benchttp
 import (
 	"time"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics"
-	"github.com/benchttp/engine/benchttp/internal/tests"
+	"github.com/benchttp/engine/benchttp/metrics"
+	"github.com/benchttp/engine/benchttp/testsuite"
 )
 
 // Report represents a run result as exported by the runner.
 type Report struct {
 	Metadata Metadata
 	Metrics  metrics.Aggregate
-	Tests    tests.SuiteResult
+	Tests    testsuite.Result
 }
 
 // Metadata contains contextual information about a run.
@@ -26,7 +26,7 @@ func newReport(
 	r Runner,
 	d time.Duration,
 	m metrics.Aggregate,
-	t tests.SuiteResult,
+	t testsuite.Result,
 ) *Report {
 	return &Report{
 		Metrics: m,
diff --git a/benchttp/runner.go b/benchttp/runner.go
index e8d1d11..bd0bebe 100644
--- a/benchttp/runner.go
+++ b/benchttp/runner.go
@@ -8,35 +8,11 @@ import (
 	"net/http"
 	"time"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics"
-	"github.com/benchttp/engine/benchttp/internal/recorder"
-	"github.com/benchttp/engine/benchttp/internal/tests"
+	"github.com/benchttp/engine/benchttp/metrics"
+	"github.com/benchttp/engine/benchttp/recorder"
+	"github.com/benchttp/engine/benchttp/testsuite"
 )
 
-type (
-	RecordingProgress = recorder.Progress
-	RecordingStatus   = recorder.Status
-
-	MetricsAggregate = metrics.Aggregate
-	MetricsField     = metrics.Field
-	MetricsValue     = metrics.Value
-	MetricsTimeStats = metrics.TimeStats
-
-	TestCase         = tests.Case
-	TestPredicate    = tests.Predicate
-	TestSuiteResults = tests.SuiteResult
-	TestCaseResult   = tests.CaseResult
-)
-
-const (
-	StatusRunning  = recorder.StatusRunning
-	StatusCanceled = recorder.StatusCanceled
-	StatusTimeout  = recorder.StatusTimeout
-	StatusDone     = recorder.StatusDone
-)
-
-var ErrCanceled = recorder.ErrCanceled
-
 type Runner struct {
 	Request *http.Request
 
@@ -46,9 +22,9 @@ type Runner struct {
 	RequestTimeout time.Duration
 	GlobalTimeout  time.Duration
 
-	Tests []tests.Case
+	Tests []testsuite.Case
 
-	OnProgress func(RecordingProgress)
+	OnProgress func(recorder.Progress)
 
 	recorder *recorder.Recorder
 }
@@ -103,7 +79,7 @@ func (r Runner) Run(ctx context.Context) (*Report, error) {
 
 	agg := metrics.NewAggregate(records)
 
-	testResults := tests.Run(agg, r.Tests)
+	testResults := testsuite.Run(agg, r.Tests)
 
 	return newReport(r, duration, agg, testResults), nil
 }
diff --git a/benchttp/internal/tests/predicate.go b/benchttp/testsuite/predicate.go
similarity index 94%
rename from benchttp/internal/tests/predicate.go
rename to benchttp/testsuite/predicate.go
index dbdee79..8fd4169 100644
--- a/benchttp/internal/tests/predicate.go
+++ b/benchttp/testsuite/predicate.go
@@ -1,9 +1,9 @@
-package tests
+package testsuite
 
 import (
 	"errors"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics"
+	"github.com/benchttp/engine/benchttp/metrics"
 	"github.com/benchttp/engine/internal/errorutil"
 )
 
diff --git a/benchttp/internal/tests/predicate_test.go b/benchttp/testsuite/predicate_test.go
similarity index 78%
rename from benchttp/internal/tests/predicate_test.go
rename to benchttp/testsuite/predicate_test.go
index bbb29b6..7704553 100644
--- a/benchttp/internal/tests/predicate_test.go
+++ b/benchttp/testsuite/predicate_test.go
@@ -1,11 +1,11 @@
-package tests_test
+package testsuite_test
 
 import (
 	"testing"
 	"time"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics"
-	"github.com/benchttp/engine/benchttp/internal/tests"
+	"github.com/benchttp/engine/benchttp/metrics"
+	"github.com/benchttp/engine/benchttp/testsuite"
 )
 
 func TestPredicate(t *testing.T) {
@@ -16,37 +16,37 @@ func TestPredicate(t *testing.T) {
 	)
 
 	testcases := []struct {
-		Predicate  tests.Predicate
+		Predicate  testsuite.Predicate
 		PassValues []int
 		FailValues []int
 	}{
 		{
-			Predicate:  tests.EQ,
+			Predicate:  testsuite.EQ,
 			PassValues: []int{base},
 			FailValues: []int{more, less},
 		},
 		{
-			Predicate:  tests.NEQ,
+			Predicate:  testsuite.NEQ,
 			PassValues: []int{less, more},
 			FailValues: []int{base},
 		},
 		{
-			Predicate:  tests.LT,
+			Predicate:  testsuite.LT,
 			PassValues: []int{more},
 			FailValues: []int{base, less},
 		},
 		{
-			Predicate:  tests.LTE,
+			Predicate:  testsuite.LTE,
 			PassValues: []int{more, base},
 			FailValues: []int{less},
 		},
 		{
-			Predicate:  tests.GT,
+			Predicate:  testsuite.GT,
 			PassValues: []int{less},
 			FailValues: []int{base, more},
 		},
 		{
-			Predicate:  tests.GTE,
+			Predicate:  testsuite.GTE,
 			PassValues: []int{less, base},
 			FailValues: []int{more},
 		},
@@ -68,7 +68,7 @@ func TestPredicate(t *testing.T) {
 
 func expectPredicatePass(
 	t *testing.T,
-	p tests.Predicate,
+	p testsuite.Predicate,
 	src, tar int,
 ) {
 	t.Helper()
@@ -77,7 +77,7 @@ func expectPredicatePass(
 
 func expectPredicateFail(
 	t *testing.T,
-	p tests.Predicate,
+	p testsuite.Predicate,
 	src, tar int,
 ) {
 	t.Helper()
@@ -86,7 +86,7 @@ func expectPredicateFail(
 
 func expectPredicateResult(
 	t *testing.T,
-	p tests.Predicate,
+	p testsuite.Predicate,
 	src, tar int,
 	expPass bool,
 ) {
@@ -98,7 +98,7 @@ func expectPredicateResult(
 		}, src),
 	}
 
-	result := tests.Run(agg, []tests.Case{{
+	result := testsuite.Run(agg, []testsuite.Case{{
 		Predicate: p,
 		Field:     "RequestCount",
 		Target:    tar,
diff --git a/benchttp/internal/tests/tests.go b/benchttp/testsuite/testsuite.go
similarity index 80%
rename from benchttp/internal/tests/tests.go
rename to benchttp/testsuite/testsuite.go
index 05a1a1e..6afc0af 100644
--- a/benchttp/internal/tests/tests.go
+++ b/benchttp/testsuite/testsuite.go
@@ -1,9 +1,9 @@
-package tests
+package testsuite
 
 import (
 	"fmt"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics"
+	"github.com/benchttp/engine/benchttp/metrics"
 )
 
 type Case struct {
@@ -13,10 +13,6 @@ type Case struct {
 	Target    metrics.Value
 }
 
-type SuiteResult struct {
-	Pass    bool
-	Results []CaseResult
-}
 
 type CaseResult struct {
 	Input   Case
@@ -25,7 +21,12 @@ type CaseResult struct {
 	Summary string
 }
 
-func Run(agg metrics.Aggregate, cases []Case) SuiteResult {
+type Result struct {
+	Pass    bool
+	OfCases []CaseResult
+}
+
+func Run(agg metrics.Aggregate, cases []Case) Result {
 	allpass := true
 	results := make([]CaseResult, len(cases))
 	for i, input := range cases {
@@ -35,9 +36,9 @@ func Run(agg metrics.Aggregate, cases []Case) SuiteResult {
 			allpass = false
 		}
 	}
-	return SuiteResult{
+	return Result{
 		Pass:    allpass,
-		Results: results,
+		OfCases: results,
 	}
 }
 
diff --git a/benchttp/internal/tests/tests_test.go b/benchttp/testsuite/testsuite_test.go
similarity index 75%
rename from benchttp/internal/tests/tests_test.go
rename to benchttp/testsuite/testsuite_test.go
index a9114ce..251a430 100644
--- a/benchttp/internal/tests/tests_test.go
+++ b/benchttp/testsuite/testsuite_test.go
@@ -1,42 +1,41 @@
-package tests_test
+package testsuite_test
 
 import (
 	"fmt"
 	"testing"
 	"time"
 
-	"github.com/benchttp/engine/benchttp/internal/metrics"
-	"github.com/benchttp/engine/benchttp/internal/metrics/timestats"
-	"github.com/benchttp/engine/benchttp/internal/tests"
+	"github.com/benchttp/engine/benchttp/metrics"
+	"github.com/benchttp/engine/benchttp/testsuite"
 )
 
 func TestRun(t *testing.T) {
 	testcases := []struct {
 		label          string
 		inputAgg       metrics.Aggregate
-		inputCases     []tests.Case
-		expGlobalPass  bool
-		expCaseResults []tests.CaseResult
+		inputCases     []testsuite.Case
+		expPass  bool
+		expCasesResults []testsuite.CaseResult
 	}{
 		{
 			label:    "pass if all cases pass",
 			inputAgg: metricsWithMeanResponseTime(ms(100)),
-			inputCases: []tests.Case{
+			inputCases: []testsuite.Case{
 				{
 					Name:      "average response time below 120ms (pass)",
-					Predicate: tests.LT,
+					Predicate: testsuite.LT,
 					Field:     "ResponseTimes.Mean",
 					Target:    ms(120),
 				},
 				{
 					Name:      "average response time is above 80ms (pass)",
-					Predicate: tests.GT,
+					Predicate: testsuite.GT,
 					Field:     "ResponseTimes.Mean",
 					Target:    ms(80),
 				},
 			},
-			expGlobalPass: true,
-			expCaseResults: []tests.CaseResult{
+			expPass: true,
+			expCasesResults: []testsuite.CaseResult{
 				{Pass: true, Got: ms(100), Summary: "want ResponseTimes.Mean < 120ms, got 100ms"},
 				{Pass: true, Got: ms(100), Summary: "want ResponseTimes.Mean > 80ms, got 100ms"},
 			},
@@ -44,22 +43,22 @@ func TestRun(t *testing.T) {
 		{
 			label:    "fail if at least one case fails",
 			inputAgg: metricsWithMeanResponseTime(ms(200)),
-			inputCases: []tests.Case{
+			inputCases: []testsuite.Case{
 				{
 					Name:      "average response time below 120ms (fail)",
-					Predicate: tests.LT,
+					Predicate: testsuite.LT,
 					Field:     "ResponseTimes.Mean",
 					Target:    ms(120),
 				},
 				{
 					Name:      "average response time is above 80ms (pass)",
-					Predicate: tests.GT,
+					Predicate: testsuite.GT,
 					Field:     "ResponseTimes.Mean",
 					Target:    ms(80),
 				},
 			},
-			expGlobalPass: false,
-			expCaseResults: []tests.CaseResult{
+			expPass: false,
+			expCasesResults: []testsuite.CaseResult{
 				{Pass: false, Got: ms(200), Summary: "want ResponseTimes.Mean < 120ms, got 200ms"},
 				{Pass: true, Got: ms(200), Summary: "want ResponseTimes.Mean > 80ms, got 200ms"},
 			},
@@ -68,10 +67,10 @@ func TestRun(t *testing.T) {
 
 	for _, tc := range testcases {
 		t.Run(tc.label, func(t *testing.T) {
-			suiteResult := tests.Run(tc.inputAgg, tc.inputCases)
+			suiteResult := testsuite.Run(tc.inputAgg, tc.inputCases)
 
-			assertGlobalPass(t, suiteResult.Pass, tc.expGlobalPass)
-			assertEqualCaseResults(t, tc.expCaseResults, suiteResult.Results)
+			assertGlobalPass(t, suiteResult.Pass, tc.expPass)
+			assertEqualCasesResults(t, tc.expCasesResults, suiteResult.OfCases)
 		})
 	}
 }
@@ -89,7 +88,7 @@ func assertGlobalPass(t *testing.T, got, exp bool) {
 	})
 }
 
-func assertEqualCaseResults(t *testing.T, exp, got []tests.CaseResult) {
+func assertEqualCasesResults(t *testing.T, exp, got []testsuite.CaseResult) {
 	t.Helper()
 
 	if gotLen, expLen := len(got), len(exp); gotLen != expLen {
@@ -131,7 +130,7 @@ func assertEqualCaseResults(t *testing.T, exp, got []tests.CaseResult) {
 
 func metricsWithMeanResponseTime(d time.Duration) metrics.Aggregate {
 	return metrics.Aggregate{
-		ResponseTimes: timestats.TimeStats{
+		ResponseTimes: metrics.TimeStats{
 			Mean: d,
 		},
 	}
diff --git a/cli/errorutil/errorutil.go b/cli/errorutil/errorutil.go
deleted file mode 100644
index d733a93..0000000
--- a/cli/errorutil/errorutil.go
+++ /dev/null
@@ -1,24 +0,0 @@
-package errorutil
-
-import (
-	"fmt"
-	"strings"
-)
-
-// WithDetails returns an error wrapping err, appended with a string
-// representation of details separated by ": ".
-//
-// Example
-//
-//	var ErrNotFound = errors.New("not found")
-//	err := WithDetails(ErrNotFound, "abc.jpg", "deleted yesterday")
-//
-//	errors.Is(err, ErrNotFound) == true
-//	err.Error() == "not found: abc.jpg: deleted yesterday"
-func WithDetails(base error, details ...interface{}) error {
-	detailsStr := make([]string, len(details))
-	for i := range details {
-		detailsStr[i] = fmt.Sprint(details[i])
-	}
-	return fmt.Errorf("%w: %s", base, strings.Join(detailsStr, ": "))
-}
diff --git a/cli/render/progress.go b/cli/render/progress.go
index 3e97a1f..00209f5 100644
--- a/cli/render/progress.go
+++ b/cli/render/progress.go
@@ -6,14 +6,14 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/benchttp/engine/benchttp"
+	"github.com/benchttp/engine/benchttp/recorder"
 
 	"github.com/benchttp/engine/cli/render/ansi"
 )
 
 // Progress renders a fancy representation of a runner.RecordingProgress
 // and writes the result to w.
-func Progress(w io.Writer, p benchttp.RecordingProgress) (int, error) {
+func Progress(w io.Writer, p recorder.Progress) (int, error) {
 	return fmt.Fprint(w, progressString(p))
 }
 
@@ -21,7 +21,7 @@ func Progress(w io.Writer, p benchttp.RecordingProgress) (int, error) {
 // for a fancy display in a CLI:
 //
 //	RUNNING ◼︎◼︎◼︎◼︎◼︎◼︎◼︎◼︎◼︎◼︎ 50% | 50/100 requests | 27s timeout
-func progressString(p benchttp.RecordingProgress) string {
+func progressString(p recorder.Progress) string {
 	var (
 		countdown = p.Timeout - p.Elapsed
 		reqmax    = strconv.Itoa(p.MaxCount)
@@ -68,20 +68,20 @@ func renderTimeline(pctdone int) string {
 // renderStatus returns a string representing the status,
 // depending on whether the run is done or not and the value
 // of its context error.
-func renderStatus(status benchttp.RecordingStatus) string {
+func renderStatus(status recorder.Status) string {
 	styled := statusStyle(status)
 	return styled(string(status))
 }
 
-func statusStyle(status benchttp.RecordingStatus) ansi.StyleFunc {
+func statusStyle(status recorder.Status) ansi.StyleFunc {
 	switch status {
-	case benchttp.StatusRunning:
+	case recorder.StatusRunning:
 		return ansi.Yellow
-	case benchttp.StatusDone:
+	case recorder.StatusDone:
 		return ansi.Green
-	case benchttp.StatusCanceled:
+	case recorder.StatusCanceled:
 		return ansi.Red
-	case benchttp.StatusTimeout:
+	case recorder.StatusTimeout:
 		return ansi.Cyan
 	}
 	return ansi.Grey // should not occur
diff --git a/cli/render/report_test.go b/cli/render/report_test.go
index 72ba406..a52f22d 100644
--- a/cli/render/report_test.go
+++ b/cli/render/report_test.go
@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/benchttp/engine/benchttp"
+	"github.com/benchttp/engine/benchttp/metrics"
 
 	"github.com/benchttp/engine/cli/render"
 	"github.com/benchttp/engine/cli/render/ansi"
@@ -29,13 +30,13 @@ func TestReport_String(t *testing.T) {
 
 // helpers
 
-func metricsStub() (agg benchttp.MetricsAggregate, total time.Duration) {
-	return benchttp.MetricsAggregate{
+func metricsStub() (agg metrics.Aggregate, total time.Duration) {
+	return metrics.Aggregate{
 		RequestFailures: make([]struct {
 			Reason string
 		}, 1),
 		Records: make([]struct{ ResponseTime time.Duration }, 3),
-		ResponseTimes: benchttp.MetricsTimeStats{
+		ResponseTimes: metrics.TimeStats{
 			Min:  4 * time.Second,
 			Max:  6 * time.Second,
 			Mean: 5 * time.Second,
diff --git a/cli/render/testsuite.go b/cli/render/testsuite.go
index 63714fd..b0cc1ef 100644
--- a/cli/render/testsuite.go
+++ b/cli/render/testsuite.go
@@ -4,18 +4,18 @@ import (
 	"io"
 	"strings"
 
-	"github.com/benchttp/engine/benchttp"
+	"github.com/benchttp/engine/benchttp/testsuite"
 
 	"github.com/benchttp/engine/cli/render/ansi"
 )
 
-func TestSuite(w io.Writer, suite benchttp.TestSuiteResults) (int, error) {
-	return w.Write([]byte(TestSuiteString(suite)))
+func TestSuite(w io.Writer, result testsuite.Result) (int, error) {
+	return w.Write([]byte(TestSuiteString(result)))
 }
 
 // String returns a default summary of the Report as a string.
-func TestSuiteString(suite benchttp.TestSuiteResults) string {
-	if len(suite.Results) == 0 {
+func TestSuiteString(result testsuite.Result) string {
+	if len(result.OfCases) == 0 {
 		return ""
 	}
 
@@ -24,10 +24,10 @@ func TestSuiteString(suite benchttp.TestSuiteResults) string {
 	b.WriteString(ansi.Bold("→ Test suite"))
 	b.WriteString("\n")
 
-	writeResultString(&b, suite.Pass)
+	writeResultString(&b, result.Pass)
 	b.WriteString("\n")
 
-	for _, tr := range suite.Results {
+	for _, tr := range result.OfCases {
 		writeIndent(&b, 1)
 		writeResultString(&b, tr.Pass)
 		b.WriteString(" ")
diff --git a/cli/testutil/http.go b/cli/testutil/http.go
deleted file mode 100644
index 34b660b..0000000
--- a/cli/testutil/http.go
+++ /dev/null
@@ -1,15 +0,0 @@
-package testutil
-
-import (
-	"bytes"
-	"net/http"
-)
-
-func MustMakeRequest(method, uri string, header http.Header, body []byte) *http.Request {
-	req, err := http.NewRequest(method, uri, bytes.NewReader(body))
-	if err != nil {
-		panic("testutil.MustMakeRequest: " + err.Error())
-	}
-	req.Header = header
-	return req
-}
diff --git a/cmd/benchttp/run.go b/cmd/benchttp/run.go
index ce84726..79fc505 100644
--- a/cmd/benchttp/run.go
+++ b/cmd/benchttp/run.go
@@ -9,6 +9,7 @@ import (
 	"os"
 
 	"github.com/benchttp/engine/benchttp"
+	"github.com/benchttp/engine/benchttp/recorder"
 	"github.com/benchttp/engine/configio"
 
 	"github.com/benchttp/engine/cli/configflag"
@@ -93,16 +94,16 @@ func runBenchmark(runner benchttp.Runner, silent bool) (*benchttp.Report, error)
 	return report, nil
 }
 
-func onRecordingProgress(silent bool) func(benchttp.RecordingProgress) {
+func onRecordingProgress(silent bool) func(recorder.Progress) {
 	if silent {
-		return func(benchttp.RecordingProgress) {}
+		return func(recorder.Progress) {}
 	}
 
 	// hack: write a blank line as render.Progress always
 	// erases the previous line
 	fmt.Println()
 
-	return func(progress benchttp.RecordingProgress) {
+	return func(progress recorder.Progress) {
 		render.Progress(os.Stdout, progress) //nolint: errcheck
 	}
 }
diff --git a/configio/builder.go b/configio/builder.go
index 2256ab1..76cef6d 100644
--- a/configio/builder.go
+++ b/configio/builder.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/benchttp/engine/benchttp"
+	"github.com/benchttp/engine/benchttp/testsuite"
 )
 
 // A Builder is used to incrementally build a benchttp.Runner
@@ -165,7 +166,7 @@ func (b *Builder) SetGlobalTimeout(v time.Duration) {
 
 // SetTests adds a mutation that sets a runner's
 // Tests field to v.
-func (b *Builder) SetTests(v []benchttp.TestCase) {
+func (b *Builder) SetTests(v []testsuite.Case) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.Tests = v
 	})
@@ -173,7 +174,7 @@ func (b *Builder) SetTests(v []benchttp.TestCase) {
 
 // SetTests adds a mutation that appends the given benchttp.TestCases
 // to a runner's Tests field.
-func (b *Builder) AddTests(v ...benchttp.TestCase) {
+func (b *Builder) AddTests(v ...testsuite.Case) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.Tests = append(runner.Tests, v...)
 	})
diff --git a/configio/builder_test.go b/configio/builder_test.go
index 7749e12..6da9d45 100644
--- a/configio/builder_test.go
+++ b/configio/builder_test.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/benchttp/engine/benchttp"
+	"github.com/benchttp/engine/benchttp/testsuite"
 	"github.com/benchttp/engine/benchttptest"
 	"github.com/benchttp/engine/configio"
 )
@@ -103,7 +104,7 @@ func TestBuilder_Set(t *testing.T) {
 
 	t.Run("test cases", func(t *testing.T) {
 		want := benchttp.Runner{
-			Tests: []benchttp.TestCase{
+			Tests: []testsuite.Case{
 				{
 					Name:      "maximum response time",
 					Field:     "ResponseTimes.Max",
@@ -126,7 +127,7 @@ func TestBuilder_Set(t *testing.T) {
 		}
 
 		b := configio.Builder{}
-		b.SetTests([]benchttp.TestCase{want.Tests[0]})
+		b.SetTests([]testsuite.Case{want.Tests[0]})
 		b.AddTests(want.Tests[1:]...)
 
 		benchttptest.AssertEqualRunners(t, want, b.Runner())
diff --git a/configio/internal/testdata/testdata.go b/configio/internal/testdata/testdata.go
index 5ed0f58..6e0efa6 100644
--- a/configio/internal/testdata/testdata.go
+++ b/configio/internal/testdata/testdata.go
@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/benchttp/engine/benchttp"
+	"github.com/benchttp/engine/benchttp/testsuite"
 )
 
 // ConfigFile represents a testdata configuration file.
@@ -128,7 +129,7 @@ func fullRunner() benchttp.Runner {
 		RequestTimeout: 2 * time.Second,
 		GlobalTimeout:  60 * time.Second,
 
-		Tests: []benchttp.TestCase{
+		Tests: []testsuite.Case{
 			{
 				Name:      "maximum response time",
 				Field:     "ResponseTimes.Max",
diff --git a/configio/representation.go b/configio/representation.go
index bf851a1..c60ec38 100644
--- a/configio/representation.go
+++ b/configio/representation.go
@@ -11,6 +11,8 @@ import (
 	"time"
 
 	"github.com/benchttp/engine/benchttp"
+	"github.com/benchttp/engine/benchttp/metrics"
+	"github.com/benchttp/engine/benchttp/testsuite"
 	"github.com/benchttp/engine/internal/errorutil"
 )
 
@@ -145,7 +147,7 @@ func (repr representation) parseTestsInto(dst *benchttp.Runner) error {
 		return nil
 	}
 
-	cases := make([]benchttp.TestCase, len(testSuite))
+	cases := make([]testsuite.Case, len(testSuite))
 	for i, t := range testSuite {
 		fieldPath := func(caseField string) string {
 			return fmt.Sprintf("tests[%d].%s", i, caseField)
@@ -160,12 +162,12 @@ func (repr representation) parseTestsInto(dst *benchttp.Runner) error {
 			return err
 		}
 
-		field := benchttp.MetricsField(*t.Field)
+		field := metrics.Field(*t.Field)
 		if err := field.Validate(); err != nil {
 			return fmt.Errorf("%s: %s", fieldPath("field"), err)
 		}
 
-		predicate := benchttp.TestPredicate(*t.Predicate)
+		predicate := testsuite.Predicate(*t.Predicate)
 		if err := predicate.Validate(); err != nil {
 			return fmt.Errorf("%s: %s", fieldPath("predicate"), err)
 		}
@@ -175,7 +177,7 @@ func (repr representation) parseTestsInto(dst *benchttp.Runner) error {
 			return fmt.Errorf("%s: %s", fieldPath("target"), err)
 		}
 
-		cases[i] = benchttp.TestCase{
+		cases[i] = testsuite.Case{
 			Name:      *t.Name,
 			Field:     field,
 			Predicate: predicate,
@@ -222,11 +224,11 @@ func parseOptionalDuration(raw string) (time.Duration, error) {
 }
 
 func parseMetricValue(
-	field benchttp.MetricsField,
+	field metrics.Field,
 	inputValue string,
-) (benchttp.MetricsValue, error) {
+) (metrics.Value, error) {
 	fieldType := field.Type()
-	handleError := func(v interface{}, err error) (benchttp.MetricsValue, error) {
+	handleError := func(v interface{}, err error) (metrics.Value, error) {
 		if err != nil {
 			return nil, fmt.Errorf(
 				"value %q is incompatible with field %s (want %s)",
diff --git a/benchttp/internal/reflectpath/resolver.go b/internal/reflectpath/resolver.go
similarity index 100%
rename from benchttp/internal/reflectpath/resolver.go
rename to internal/reflectpath/resolver.go
diff --git a/benchttp/internal/reflectpath/type.go b/internal/reflectpath/type.go
similarity index 100%
rename from benchttp/internal/reflectpath/type.go
rename to internal/reflectpath/type.go
diff --git a/benchttp/internal/reflectpath/value.go b/internal/reflectpath/value.go
similarity index 100%
rename from benchttp/internal/reflectpath/value.go
rename to internal/reflectpath/value.go
diff --git a/internal/dispatcher/dispatcher.go b/internal/workerpool/workerpool.go
similarity index 89%
rename from internal/dispatcher/dispatcher.go
rename to internal/workerpool/workerpool.go
index b02eba5..3088b09 100644
--- a/internal/dispatcher/dispatcher.go
+++ b/internal/workerpool/workerpool.go
@@ -1,4 +1,4 @@
-package dispatcher
+package workerpool
 
 import (
 	"context"
@@ -15,7 +15,7 @@ type Dispatcher interface {
 	Do(ctx context.Context, maxIter int, callback func()) error
 }
 
-type dispatcher struct {
+type workerpool struct {
 	numWorker int
 	sem       *semaphore.Weighted
 }
@@ -26,7 +26,7 @@ func New(numWorker int) Dispatcher {
 		panic(fmt.Sprintf("invalid numWorker value: must be > 1, got %d", numWorker))
 	}
 	sem := semaphore.NewWeighted(int64(numWorker))
-	return dispatcher{sem: sem, numWorker: numWorker}
+	return workerpool{sem: sem, numWorker: numWorker}
 }
 
 // Do concurrently executes callback at most maxIter times or until ctx is done
@@ -39,7 +39,7 @@ func New(numWorker int) Dispatcher {
 //	callback == nil
 //
 // Else it returns the context error if any or nil.
-func (d dispatcher) Do(ctx context.Context, maxIter int, callback func()) error {
+func (d workerpool) Do(ctx context.Context, maxIter int, callback func()) error {
 	if err := d.validate(maxIter, callback); err != nil {
 		return err
 	}
@@ -72,7 +72,7 @@ func (d dispatcher) Do(ctx context.Context, maxIter int, callback func()) error
 	return err
 }
 
-func (d dispatcher) validate(maxIter int, callback func()) error {
+func (d workerpool) validate(maxIter int, callback func()) error {
 	if maxIter < 1 && maxIter != -1 {
 		return fmt.Errorf("%w: maxIter: must be -1 or >= 1, got %d", ErrInvalidValue, maxIter)
 	}
diff --git a/internal/dispatcher/dispatcher_test.go b/internal/workerpool/workerpool_test.go
similarity index 91%
rename from internal/dispatcher/dispatcher_test.go
rename to internal/workerpool/workerpool_test.go
index 6b5d9bd..f8b7221 100644
--- a/internal/dispatcher/dispatcher_test.go
+++ b/internal/workerpool/workerpool_test.go
@@ -1,4 +1,4 @@
-package dispatcher_test
+package workerpool_test
 
 import (
 	"context"
@@ -9,7 +9,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/benchttp/engine/internal/dispatcher"
+	"github.com/benchttp/engine/internal/workerpool"
 )
 
 func TestNew(t *testing.T) {
@@ -31,7 +31,7 @@ func TestNew(t *testing.T) {
 					}
 				}()
 
-				if d := dispatcher.New(numWorker); d != nil {
+				if d := workerpool.New(numWorker); d != nil {
 					t.Error("returned a non-nil Dispatcher")
 				}
 			}(numWorker)
@@ -39,7 +39,7 @@ func TestNew(t *testing.T) {
 	})
 
 	t.Run("return valid Dispatcher if numWorker > 0", func(t *testing.T) {
-		if d := dispatcher.New(10); d == nil {
+		if d := workerpool.New(10); d == nil {
 			t.Error("returned nil Dispatcher")
 		}
 	})
@@ -55,7 +55,7 @@ func TestDo(t *testing.T) {
 
 		gotIter := 0
 
-		dispatcher.New(numWorker).Do(context.Background(), maxIter, func() { //nolint:errcheck
+		workerpool.New(numWorker).Do(context.Background(), maxIter, func() { //nolint:errcheck
 			gotIter++
 		})
 
@@ -85,7 +85,7 @@ func TestDo(t *testing.T) {
 
 		var gotErr error
 		gotDuration := timeFunc(func() {
-			gotErr = dispatcher.New(numWorker).Do(ctx, maxIter, func() {
+			gotErr = workerpool.New(numWorker).Do(ctx, maxIter, func() {
 				gotIter++
 				time.Sleep(interval)
 			})
@@ -134,7 +134,7 @@ func TestDo(t *testing.T) {
 
 		var gotErr error
 		gotDuration := timeFunc(func() {
-			gotErr = dispatcher.New(numWorker).Do(ctx, maxIter, func() {
+			gotErr = workerpool.New(numWorker).Do(ctx, maxIter, func() {
 				gotIter++
 				time.Sleep(interval)
 			})
@@ -177,7 +177,7 @@ func TestDo(t *testing.T) {
 			gotNumGoroutines = make([]int, 0, maxIter)
 		)
 
-		dispatcher.New(numWorker).Do(context.Background(), maxIter, func() { //nolint:errcheck
+		workerpool.New(numWorker).Do(context.Background(), maxIter, func() { //nolint:errcheck
 			mu.Lock()
 			gotNumGoroutines = append(gotNumGoroutines, runtime.NumGoroutine()-baseNumGoroutine)
 			mu.Unlock()
@@ -213,7 +213,7 @@ func TestDo(t *testing.T) {
 		)
 
 		start := time.Now()
-		dispatcher.New(numWorker).Do(context.Background(), maxIter, func() { //nolint:errcheck
+		workerpool.New(numWorker).Do(context.Background(), maxIter, func() { //nolint:errcheck
 			mu.Lock()
 			elapsedTimes = append(elapsedTimes, time.Since(start))
 			mu.Unlock()
@@ -267,28 +267,28 @@ func TestValidate(t *testing.T) {
 	}{
 		{
 			label:     "return error if maxIter == 0",
-			exp:       dispatcher.ErrInvalidValue,
+			exp:       workerpool.ErrInvalidValue,
 			numWorker: 10,
 			maxIter:   0,
 			callback:  func() {},
 		},
 		{
 			label:     "return error if maxIter == -2",
-			exp:       dispatcher.ErrInvalidValue,
+			exp:       workerpool.ErrInvalidValue,
 			numWorker: 10,
 			maxIter:   -2,
 			callback:  func() {},
 		},
 		{
 			label:     "return error if maxIter < numWorker",
-			exp:       dispatcher.ErrInvalidValue,
+			exp:       workerpool.ErrInvalidValue,
 			numWorker: 10,
 			maxIter:   5,
 			callback:  func() {},
 		},
 		{
 			label:     "return error if callback == nil",
-			exp:       dispatcher.ErrInvalidValue,
+			exp:       workerpool.ErrInvalidValue,
 			numWorker: 10,
 			maxIter:   20,
 			callback:  nil,
@@ -314,7 +314,7 @@ func TestValidate(t *testing.T) {
 			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Millisecond)
 			defer cancel()
 
-			gotErr := dispatcher.New(tc.numWorker).Do(ctx, tc.maxIter, tc.callback)
+			gotErr := workerpool.New(tc.numWorker).Do(ctx, tc.maxIter, tc.callback)
 			if !errors.Is(gotErr, tc.exp) {
 				t.Errorf("unexpected error:\nexp %v\ngot %v", tc.exp, gotErr)
 			}