diff --git a/pkg/receive/capnp_server.go b/pkg/receive/capnp_server.go
index f6c0282460..34b406bfa9 100644
--- a/pkg/receive/capnp_server.go
+++ b/pkg/receive/capnp_server.go
@@ -103,35 +103,6 @@ func (c CapNProtoHandler) Write(ctx context.Context, call writecapnp.Writer_writ
 			result.SetError(writecapnp.WriteError_internal)
 		}
 	}
-	return nil
-}
-
-type BufferedListener struct {
-	ctx    context.Context
-	cancel context.CancelFunc
-
-	conns chan net.Conn
-}
-
-func (b BufferedListener) Accept() (net.Conn, error) {
-	select {
-	case <-b.ctx.Done():
-		return nil, b.ctx.Err()
-	case c := <-b.conns:
-		return c, nil
-	}
-}
 
-func (b BufferedListener) Close() error {
-	b.cancel()
 	return nil
 }
-
-func (b BufferedListener) Addr() net.Addr {
-	return addr{}
-}
-
-type addr struct{}
-
-func (addr) Network() string { return "bufconn" }
-func (addr) String() string  { return "bufconn" }
diff --git a/pkg/receive/capnproto_writer.go b/pkg/receive/capnproto_writer.go
index 00b484f436..115605a6dd 100644
--- a/pkg/receive/capnproto_writer.go
+++ b/pkg/receive/capnproto_writer.go
@@ -5,6 +5,7 @@ package receive
 
 import (
 	"context"
+	"strings"
 
 	"github.com/go-kit/log"
 	"github.com/pkg/errors"
@@ -72,6 +73,13 @@ func (r *CapNProtoWriter) Write(ctx context.Context, tenantID string, wreq *writ
 		ref, lset = getRef.GetRef(series.Labels, series.Labels.Hash())
 		if ref == 0 {
 			lset = series.Labels.Copy()
+			// NOTE(GiedriusS): do a deep copy because the labels are reused in the capnp message.
+			// Creation of new series is much rarer compared to adding extra samples
+			// to an existing series.
+			for i := range lset {
+				lset[i].Name = strings.Clone(lset[i].Name)
+				lset[i].Value = strings.Clone(lset[i].Value)
+			}
 		}
 
 		// Append as many valid samples as possible, but keep track of the errors.
diff --git a/test/e2e/e2ethanos/services.go b/test/e2e/e2ethanos/services.go
index 0ae6dd8d7a..c8a9e7fc62 100644
--- a/test/e2e/e2ethanos/services.go
+++ b/test/e2e/e2ethanos/services.go
@@ -539,6 +539,7 @@ type ReceiveBuilder struct {
 	f e2e.FutureRunnable
 
 	maxExemplars        int
+	capnp               bool
 	ingestion           bool
 	limit               int
 	tenantsLimits       receive.TenantsWriteLimitsConfig
@@ -555,7 +556,7 @@ type ReceiveBuilder struct {
 
 func NewReceiveBuilder(e e2e.Environment, name string) *ReceiveBuilder {
 	f := e.Runnable(fmt.Sprintf("receive-%v", name)).
-		WithPorts(map[string]int{"http": 8080, "grpc": 9091, "remote-write": 8081}).
+		WithPorts(map[string]int{"http": 8080, "grpc": 9091, "remote-write": 8081, "capnp": 19391}).
 		Future()
 	return &ReceiveBuilder{
 		Linkable:    f,
@@ -586,6 +587,11 @@ func (r *ReceiveBuilder) WithLabel(name, value string) *ReceiveBuilder {
 	return r
 }
 
+func (r *ReceiveBuilder) UseCapnpReplication() *ReceiveBuilder {
+	r.capnp = true
+	return r
+}
+
 func (r *ReceiveBuilder) WithRouting(replication int, hashringConfigs ...receive.HashringConfig) *ReceiveBuilder {
 	r.hashringConfigs = hashringConfigs
 	r.replication = replication
@@ -646,6 +652,10 @@ func (r *ReceiveBuilder) Init() *e2eobs.Observable {
 		args["--label"] = fmt.Sprintf("%s,%s", args["--label"], strings.Join(r.labels, ","))
 	}
 
+	if r.capnp {
+		args["--receive.replication-protocol"] = "capnproto"
+	}
+
 	hashring := r.hashringConfigs
 	if len(hashring) > 0 && r.ingestion {
 		args["--receive.local-endpoint"] = r.InternalEndpoint("grpc")
diff --git a/test/e2e/receive_test.go b/test/e2e/receive_test.go
index 4f70479dfc..c938a4f040 100644
--- a/test/e2e/receive_test.go
+++ b/test/e2e/receive_test.go
@@ -25,6 +25,7 @@ import (
 	"github.com/prometheus/common/model"
 
 	"github.com/prometheus/prometheus/model/relabel"
+	"github.com/prometheus/prometheus/model/timestamp"
 	"github.com/prometheus/prometheus/prompb"
 	"github.com/prometheus/prometheus/storage/remote"
 	"github.com/stretchr/testify/require"
@@ -1152,3 +1153,65 @@ func TestReceiveExtractsTenant(t *testing.T) {
 
 	})
 }
+
+func TestReceiveCpnp(t *testing.T) {
+	e, err := e2e.NewDockerEnvironment("receive-cpnp")
+	testutil.Ok(t, err)
+	t.Cleanup(e2ethanos.CleanScenario(t, e))
+
+	i := e2ethanos.NewReceiveBuilder(e, "ingestor").WithIngestionEnabled().Init()
+	testutil.Ok(t, e2e.StartAndWaitReady(i))
+
+	h := receive.HashringConfig{
+		TenantMatcherType: "glob",
+		Tenants: []string{
+			"default*",
+		},
+		Endpoints: []receive.Endpoint{
+			{Address: i.InternalEndpoint("grpc"), CapNProtoAddress: i.InternalEndpoint("capnp")},
+		},
+	}
+
+	r := e2ethanos.NewReceiveBuilder(e, "router").UseCapnpReplication().WithRouting(1, h).Init()
+	testutil.Ok(t, e2e.StartAndWaitReady(r))
+
+	ts := time.Now()
+
+	require.NoError(t, runutil.RetryWithLog(logkit.NewLogfmtLogger(os.Stdout), 1*time.Second, make(<-chan struct{}), func() error {
+		return storeWriteRequest(context.Background(), "http://"+r.Endpoint("remote-write")+"/api/v1/receive", &prompb.WriteRequest{
+			Timeseries: []prompb.TimeSeries{
+				{
+					Labels: []prompb.Label{
+						{Name: model.MetricNameLabel, Value: "myself"},
+					},
+					Samples: []prompb.Sample{
+						{Value: 1, Timestamp: timestamp.FromTime(ts)},
+					},
+				},
+			},
+		})
+	}))
+
+	testutil.Ok(t, i.WaitSumMetricsWithOptions(e2emon.Equals(0), []string{"prometheus_tsdb_blocks_loaded"}, e2emon.WithLabelMatchers(matchers.MustNewMatcher(matchers.MatchEqual, "tenant", "default-tenant")), e2emon.WaitMissingMetrics()))
+
+	q := e2ethanos.NewQuerierBuilder(e, "1", i.InternalEndpoint("grpc")).Init()
+	testutil.Ok(t, e2e.StartAndWaitReady(q))
+
+	v := instantQuery(t, context.Background(), q.Endpoint("http"), func() string { return "myself" }, func() time.Time { return ts }, promclient.QueryOptions{
+		Deduplicate: false,
+	}, 1)
+
+	v[0].Timestamp = 0
+
+	require.Equal(t, model.Vector{
+		{
+			Metric: model.Metric{
+				model.MetricNameLabel: "myself",
+				"receive":             "receive-ingestor",
+				"tenant_id":           "default-tenant",
+			},
+			Value: 1,
+		},
+	}, v)
+
+}