diff --git a/runner/clients/baserethnode/metrics.go b/runner/clients/baserethnode/metrics.go
index 28f2de2..122c795 100644
--- a/runner/clients/baserethnode/metrics.go
+++ b/runner/clients/baserethnode/metrics.go
@@ -65,7 +65,11 @@ func (r *metricsCollector) GetMetricTypes() map[string]bool {
 }
 
 func (r *metricsCollector) Collect(ctx context.Context, m *metrics.BlockMetrics) error {
-	resp, err := http.Get(r.GetMetricsEndpoint())
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, r.GetMetricsEndpoint(), nil)
+	if err != nil {
+		return fmt.Errorf("failed to create metrics request: %w", err)
+	}
+	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return fmt.Errorf("failed to get metrics: %w", err)
 	}
diff --git a/runner/clients/baserethnode/metrics_http_test.go b/runner/clients/baserethnode/metrics_http_test.go
new file mode 100644
index 0000000..b5b85fe
--- /dev/null
+++ b/runner/clients/baserethnode/metrics_http_test.go
@@ -0,0 +1,86 @@
+package baserethnode
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/base/base-bench/runner/metrics"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+func TestMetricsCollectorCollect(t *testing.T) {
+	const body = "# TYPE reth_sync_execution_execution_duration gauge\nreth_sync_execution_execution_duration 42\n"
+	for _, stage := range []string{"success", "waiting_for_headers", "reading_body"} {
+		t.Run(stage, func(t *testing.T) {
+			started := make(chan struct{})
+			release := make(chan struct{})
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				if stage == "reading_body" {
+					_, _ = io.WriteString(w, body[:len(body)/2])
+					w.(http.Flusher).Flush()
+				}
+				close(started)
+				if stage != "success" {
+					select {
+					case <-r.Context().Done():
+					case <-release:
+					}
+					return
+				}
+				_, _ = io.WriteString(w, body)
+			}))
+			t.Cleanup(func() {
+				// Release the handler even if a broken collector ignores cancellation.
+				close(release)
+				server.Close()
+			})
+
+			port := server.Listener.Addr().(*net.TCPAddr).Port
+			collector := newMetricsCollector(log.New(), nil, port)
+			block := metrics.NewBlockMetrics()
+			ctx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+			done := make(chan error, 1)
+			go func() { done <- collector.Collect(ctx, block) }()
+
+			select {
+			case <-started:
+			case <-time.After(3 * time.Second):
+				t.Fatal("metrics request did not reach the server")
+			}
+			if stage != "success" {
+				cancel()
+			}
+			var err error
+			select {
+			case err = <-done:
+			case <-time.After(3 * time.Second):
+				t.Fatal("Collect did not return after cancellation")
+			}
+			if stage != "success" {
+				if !errors.Is(err, context.Canceled) {
+					t.Fatalf("Collect error = %v, want context.Canceled", err)
+				}
+				if len(collector.GetMetrics()) != 0 {
+					t.Fatal("cancelled scrape recorded a block")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("Collect: %v", err)
+			}
+			if got := block.ExecutionMetrics["reth_sync_execution_execution_duration"]; got != float64(42) {
+				t.Fatalf("collected metric = %v, want 42", got)
+			}
+			if got := collector.GetMetrics(); len(got) != 1 || got[0].ExecutionMetrics["reth_sync_execution_execution_duration"] != float64(42) {
+				t.Fatalf("recorded metrics = %v, want one block containing 42", got)
+			}
+		})
+	}
+}
diff --git a/runner/clients/builder/metrics.go b/runner/clients/builder/metrics.go
index 5c0152a..3540636 100644
--- a/runner/clients/builder/metrics.go
+++ b/runner/clients/builder/metrics.go
@@ -148,7 +148,11 @@ func (r *metricsCollector) GetMetricTypes() map[string]bool {
 }
 
 func (r *metricsCollector) Collect(ctx context.Context, m *metrics.BlockMetrics) error {
-	resp, err := http.Get(r.GetMetricsEndpoint())
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, r.GetMetricsEndpoint(), nil)
+	if err != nil {
+		return fmt.Errorf("failed to create metrics request: %w", err)
+	}
+	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return fmt.Errorf("failed to get metrics: %w", err)
 	}
diff --git a/runner/clients/builder/metrics_http_test.go b/runner/clients/builder/metrics_http_test.go
new file mode 100644
index 0000000..bee65f2
--- /dev/null
+++ b/runner/clients/builder/metrics_http_test.go
@@ -0,0 +1,86 @@
+package builder
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/base/base-bench/runner/metrics"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+func TestMetricsCollectorCollect(t *testing.T) {
+	const body = "# TYPE reth_sync_execution_execution_duration gauge\nreth_sync_execution_execution_duration 42\n"
+	for _, stage := range []string{"success", "waiting_for_headers", "reading_body"} {
+		t.Run(stage, func(t *testing.T) {
+			started := make(chan struct{})
+			release := make(chan struct{})
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				if stage == "reading_body" {
+					_, _ = io.WriteString(w, body[:len(body)/2])
+					w.(http.Flusher).Flush()
+				}
+				close(started)
+				if stage != "success" {
+					select {
+					case <-r.Context().Done():
+					case <-release:
+					}
+					return
+				}
+				_, _ = io.WriteString(w, body)
+			}))
+			t.Cleanup(func() {
+				// Release the handler even if a broken collector ignores cancellation.
+				close(release)
+				server.Close()
+			})
+
+			port := server.Listener.Addr().(*net.TCPAddr).Port
+			collector := newMetricsCollector(log.New(), nil, port)
+			block := metrics.NewBlockMetrics()
+			ctx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+			done := make(chan error, 1)
+			go func() { done <- collector.Collect(ctx, block) }()
+
+			select {
+			case <-started:
+			case <-time.After(3 * time.Second):
+				t.Fatal("metrics request did not reach the server")
+			}
+			if stage != "success" {
+				cancel()
+			}
+			var err error
+			select {
+			case err = <-done:
+			case <-time.After(3 * time.Second):
+				t.Fatal("Collect did not return after cancellation")
+			}
+			if stage != "success" {
+				if !errors.Is(err, context.Canceled) {
+					t.Fatalf("Collect error = %v, want context.Canceled", err)
+				}
+				if len(collector.GetMetrics()) != 0 {
+					t.Fatal("cancelled scrape recorded a block")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("Collect: %v", err)
+			}
+			if got := block.ExecutionMetrics["reth_sync_execution_execution_duration"]; got != float64(42) {
+				t.Fatalf("collected metric = %v, want 42", got)
+			}
+			if got := collector.GetMetrics(); len(got) != 1 || got[0].ExecutionMetrics["reth_sync_execution_execution_duration"] != float64(42) {
+				t.Fatalf("recorded metrics = %v, want one block containing 42", got)
+			}
+		})
+	}
+}
diff --git a/runner/clients/geth/metrics.go b/runner/clients/geth/metrics.go
index b3755db..d9a5751 100644
--- a/runner/clients/geth/metrics.go
+++ b/runner/clients/geth/metrics.go
@@ -55,7 +55,11 @@ func (g *metricsCollector) GetMetrics() []metrics.BlockMetrics {
 }
 
 func (g *metricsCollector) Collect(ctx context.Context, metrics *metrics.BlockMetrics) error {
-	resp, err := http.Get(g.GetMetricsEndpoint())
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, g.GetMetricsEndpoint(), nil)
+	if err != nil {
+		return fmt.Errorf("failed to create metrics request: %w", err)
+	}
+	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return fmt.Errorf("failed to get metrics: %w", err)
 	}
diff --git a/runner/clients/geth/metrics_http_test.go b/runner/clients/geth/metrics_http_test.go
new file mode 100644
index 0000000..0e54e59
--- /dev/null
+++ b/runner/clients/geth/metrics_http_test.go
@@ -0,0 +1,86 @@
+package geth
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/base/base-bench/runner/metrics"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+func TestMetricsCollectorCollect(t *testing.T) {
+	const body = "{\"chain/execution.50-percentile\": 42}"
+	for _, stage := range []string{"success", "waiting_for_headers", "reading_body"} {
+		t.Run(stage, func(t *testing.T) {
+			started := make(chan struct{})
+			release := make(chan struct{})
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				if stage == "reading_body" {
+					_, _ = io.WriteString(w, body[:len(body)/2])
+					w.(http.Flusher).Flush()
+				}
+				close(started)
+				if stage != "success" {
+					select {
+					case <-r.Context().Done():
+					case <-release:
+					}
+					return
+				}
+				_, _ = io.WriteString(w, body)
+			}))
+			t.Cleanup(func() {
+				// Release the handler even if a broken collector ignores cancellation.
+				close(release)
+				server.Close()
+			})
+
+			port := server.Listener.Addr().(*net.TCPAddr).Port
+			collector := newMetricsCollector(log.New(), nil, port)
+			block := metrics.NewBlockMetrics()
+			ctx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+			done := make(chan error, 1)
+			go func() { done <- collector.Collect(ctx, block) }()
+
+			select {
+			case <-started:
+			case <-time.After(3 * time.Second):
+				t.Fatal("metrics request did not reach the server")
+			}
+			if stage != "success" {
+				cancel()
+			}
+			var err error
+			select {
+			case err = <-done:
+			case <-time.After(3 * time.Second):
+				t.Fatal("Collect did not return after cancellation")
+			}
+			if stage != "success" {
+				if !errors.Is(err, context.Canceled) {
+					t.Fatalf("Collect error = %v, want context.Canceled", err)
+				}
+				if len(collector.GetMetrics()) != 0 {
+					t.Fatal("cancelled scrape recorded a block")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("Collect: %v", err)
+			}
+			if got := block.ExecutionMetrics["chain/execution.50-percentile"]; got != float64(42) {
+				t.Fatalf("collected metric = %v, want 42", got)
+			}
+			if got := collector.GetMetrics(); len(got) != 1 || got[0].ExecutionMetrics["chain/execution.50-percentile"] != float64(42) {
+				t.Fatalf("recorded metrics = %v, want one block containing 42", got)
+			}
+		})
+	}
+}
diff --git a/runner/clients/reth/metrics.go b/runner/clients/reth/metrics.go
index 4cf17d2..5f8b794 100644
--- a/runner/clients/reth/metrics.go
+++ b/runner/clients/reth/metrics.go
@@ -52,7 +52,11 @@ func (r *metricsCollector) GetMetricTypes() map[string]bool {
 }
 
 func (r *metricsCollector) Collect(ctx context.Context, m *metrics.BlockMetrics) error {
-	resp, err := http.Get(r.GetMetricsEndpoint())
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, r.GetMetricsEndpoint(), nil)
+	if err != nil {
+		return fmt.Errorf("failed to create metrics request: %w", err)
+	}
+	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return fmt.Errorf("failed to get metrics: %w", err)
 	}
diff --git a/runner/clients/reth/metrics_http_test.go b/runner/clients/reth/metrics_http_test.go
new file mode 100644
index 0000000..356a200
--- /dev/null
+++ b/runner/clients/reth/metrics_http_test.go
@@ -0,0 +1,86 @@
+package reth
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/base/base-bench/runner/metrics"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+func TestMetricsCollectorCollect(t *testing.T) {
+	const body = "# TYPE reth_sync_execution_execution_duration gauge\nreth_sync_execution_execution_duration 42\n"
+	for _, stage := range []string{"success", "waiting_for_headers", "reading_body"} {
+		t.Run(stage, func(t *testing.T) {
+			started := make(chan struct{})
+			release := make(chan struct{})
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				if stage == "reading_body" {
+					_, _ = io.WriteString(w, body[:len(body)/2])
+					w.(http.Flusher).Flush()
+				}
+				close(started)
+				if stage != "success" {
+					select {
+					case <-r.Context().Done():
+					case <-release:
+					}
+					return
+				}
+				_, _ = io.WriteString(w, body)
+			}))
+			t.Cleanup(func() {
+				// Release the handler even if a broken collector ignores cancellation.
+				close(release)
+				server.Close()
+			})
+
+			port := server.Listener.Addr().(*net.TCPAddr).Port
+			collector := newMetricsCollector(log.New(), nil, port)
+			block := metrics.NewBlockMetrics()
+			ctx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+			done := make(chan error, 1)
+			go func() { done <- collector.Collect(ctx, block) }()
+
+			select {
+			case <-started:
+			case <-time.After(3 * time.Second):
+				t.Fatal("metrics request did not reach the server")
+			}
+			if stage != "success" {
+				cancel()
+			}
+			var err error
+			select {
+			case err = <-done:
+			case <-time.After(3 * time.Second):
+				t.Fatal("Collect did not return after cancellation")
+			}
+			if stage != "success" {
+				if !errors.Is(err, context.Canceled) {
+					t.Fatalf("Collect error = %v, want context.Canceled", err)
+				}
+				if len(collector.GetMetrics()) != 0 {
+					t.Fatal("cancelled scrape recorded a block")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("Collect: %v", err)
+			}
+			if got := block.ExecutionMetrics["reth_sync_execution_execution_duration"]; got != float64(42) {
+				t.Fatalf("collected metric = %v, want 42", got)
+			}
+			if got := collector.GetMetrics(); len(got) != 1 || got[0].ExecutionMetrics["reth_sync_execution_execution_duration"] != float64(42) {
+				t.Fatalf("recorded metrics = %v, want one block containing 42", got)
+			}
+		})
+	}
+}