diff --git a/exporter/splunkhecexporter/buffer.go b/exporter/splunkhecexporter/buffer.go
index e12481ccd52d0..28eda90b7ba24 100644
--- a/exporter/splunkhecexporter/buffer.go
+++ b/exporter/splunkhecexporter/buffer.go
@@ -20,6 +20,8 @@ import (
 	"errors"
 	"io"
 	"sync"
+
+	jsoniter "github.com/json-iterator/go"
 )
 
 var (
@@ -36,6 +38,7 @@ type bufferState struct {
 	maxEventLength       uint
 	writer               io.Writer
 	buf                  *bytes.Buffer
+	jsonStream           *jsoniter.Stream
 	rawLength            int
 }
 
@@ -195,15 +198,18 @@ func (p bufferStatePool) put(bf *bufferState) {
 	p.pool.Put(bf)
 }
 
+const initBufferCap = 512
+
 func newBufferStatePool(bufCap uint, compressionAvailable bool, maxEventLength uint) bufferStatePool {
 	return bufferStatePool{
 		&sync.Pool{
 			New: func() interface{} {
-				buf := new(bytes.Buffer)
+				buf := bytes.NewBuffer(make([]byte, 0, initBufferCap))
 				return &bufferState{
 					compressionAvailable: compressionAvailable,
 					writer:               &cancellableBytesWriter{innerWriter: buf, maxCapacity: bufCap},
 					buf:                  buf,
+					jsonStream:           jsoniter.NewStream(jsoniter.ConfigDefault, nil, initBufferCap),
 					bufferMaxLen:         bufCap,
 					maxEventLength:       maxEventLength,
 				}
diff --git a/exporter/splunkhecexporter/client.go b/exporter/splunkhecexporter/client.go
index aa40d12440323..1350b7353a358 100644
--- a/exporter/splunkhecexporter/client.go
+++ b/exporter/splunkhecexporter/client.go
@@ -204,9 +204,10 @@ func (c *client) fillLogsBuffer(logs plog.Logs, bs *bufferState, is iterState) (
 				} else {
 					// Parsing log record to Splunk event.
 					event := mapLogRecordToSplunkEvent(rl.Resource(), logRecord, c.config)
+
 					// JSON encoding event and writing to buffer.
 					var err error
-					b, err = jsoniter.Marshal(event)
+					b, err = marshalEvent(event, bs.jsonStream)
 					if err != nil {
 						permanentErrors = append(permanentErrors, consumererror.NewPermanent(fmt.Errorf(
 							"dropped log event: %v, error: %w", event, err)))
@@ -261,7 +262,7 @@ func (c *client) fillMetricsBuffer(metrics pmetric.Metrics, bs *bufferState, is
 				}
 				for _, event := range events {
 					// JSON encoding event and writing to buffer.
-					b, err := jsoniter.Marshal(event)
+					b, err := marshalEvent(event, bs.jsonStream)
 					if err != nil {
 						permanentErrors = append(permanentErrors, consumererror.NewPermanent(fmt.Errorf("dropped metric event: %v, error: %w", event, err)))
 						continue
@@ -305,8 +306,9 @@ func (c *client) fillTracesBuffer(traces ptrace.Traces, bs *bufferState, is iter
 
 				// Parsing span record to Splunk event.
 				event := mapSpanToSplunkEvent(rs.Resource(), span, c.config)
+
 				// JSON encoding event and writing to buffer.
-				b, err := jsoniter.Marshal(event)
+				b, err := marshalEvent(event, bs.jsonStream)
 				if err != nil {
 					permanentErrors = append(permanentErrors, consumererror.NewPermanent(fmt.Errorf("dropped span events: %v, error: %w", event, err)))
 					continue
@@ -597,3 +599,14 @@ func buildHTTPHeaders(config *Config, buildInfo component.BuildInfo) map[string]
 		"__splunk_app_version": config.SplunkAppVersion,
 	}
 }
+
+// marshalEvent marshals an event to JSON using a reusable jsoniter stream.
+func marshalEvent(event *splunk.Event, stream *jsoniter.Stream) ([]byte, error) {
+	stream.Reset(nil)
+	stream.Error = nil
+	stream.WriteVal(event)
+	if stream.Error != nil {
+		return nil, stream.Error
+	}
+	return stream.Buffer(), nil
+}
diff --git a/exporter/splunkhecexporter/client_test.go b/exporter/splunkhecexporter/client_test.go
index 5b5b67d7cce57..9956fe189bb4b 100644
--- a/exporter/splunkhecexporter/client_test.go
+++ b/exporter/splunkhecexporter/client_test.go
@@ -25,6 +25,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"os"
 	"regexp"
 	"sort"
 	"strings"
@@ -866,6 +867,57 @@ func TestReceiveRaw(t *testing.T) {
 	}
 }
 
+func TestReceiveLogEvent(t *testing.T) {
+	logs := createLogData(1, 1, 1)
+	cfg := NewFactory().CreateDefaultConfig().(*Config)
+	cfg.DisableCompression = true
+
+	actual, err := runLogExport(cfg, logs, 1, t)
+	assert.Len(t, actual, 1)
+	assert.NoError(t, err)
+
+	compareWithTestData(t, actual[0].body, "testdata/hec_log_event.json")
+}
+
+func TestReceiveMetricEvent(t *testing.T) {
+	metrics := createMetricsData(1)
+	cfg := NewFactory().CreateDefaultConfig().(*Config)
+	cfg.DisableCompression = true
+
+	actual, err := runMetricsExport(cfg, metrics, 1, t)
+	assert.Len(t, actual, 1)
+	assert.NoError(t, err)
+
+	compareWithTestData(t, actual[0].body, "testdata/hec_metric_event.json")
+}
+
+func TestReceiveSpanEvent(t *testing.T) {
+	traces := createTraceData(1)
+	cfg := NewFactory().CreateDefaultConfig().(*Config)
+	cfg.DisableCompression = true
+
+	actual, err := runTraceExport(cfg, traces, 1, t)
+	assert.Len(t, actual, 1)
+	assert.NoError(t, err)
+
+	compareWithTestData(t, actual[0].body, "testdata/hec_span_event.json")
+}
+
+// compareWithTestData compares hec output with a json file using maps instead of strings to avoid key ordering
+// issues (jsoniter doesn't sort the keys).
+func compareWithTestData(t *testing.T, actual []byte, file string) {
+	wantStr, err := os.ReadFile(file)
+	require.NoError(t, err)
+	wantMap := map[string]any{}
+	err = jsoniter.Unmarshal(wantStr, &wantMap)
+	require.NoError(t, err)
+
+	gotMap := map[string]any{}
+	err = jsoniter.Unmarshal(actual, &gotMap)
+	require.NoError(t, err)
+	assert.Equal(t, wantMap, gotMap)
+}
+
 func TestReceiveMetrics(t *testing.T) {
 	md := createMetricsData(3)
 	cfg := NewFactory().CreateDefaultConfig().(*Config)
diff --git a/exporter/splunkhecexporter/testdata/hec_log_event.json b/exporter/splunkhecexporter/testdata/hec_log_event.json
new file mode 100644
index 0000000000000..bd64c54360a66
--- /dev/null
+++ b/exporter/splunkhecexporter/testdata/hec_log_event.json
@@ -0,0 +1,11 @@
+{
+  "host": "myhost",
+  "source": "myapp",
+  "sourcetype": "myapp-type",
+  "index": "myindex",
+  "event": "mylog",
+  "fields": {
+    "otel.log.name": "0_0_0",
+    "custom": "custom"
+  }
+}
diff --git a/exporter/splunkhecexporter/testdata/hec_metric_event.json b/exporter/splunkhecexporter/testdata/hec_metric_event.json
new file mode 100644
index 0000000000000..20858fa9fe331
--- /dev/null
+++ b/exporter/splunkhecexporter/testdata/hec_metric_event.json
@@ -0,0 +1,14 @@
+{
+  "host": "unknown",
+  "event": "metric",
+  "fields": {
+    "k/n1": "vn1",
+    "k/r0": "vr0",
+    "k/r1": "vr1",
+    "metric_name:gauge_double_with_dims": 1234.5678,
+    "metric_type": "Gauge",
+    "k0": "v0",
+    "k1": "v1",
+    "k/n0": "vn0"
+  }
+}
diff --git a/exporter/splunkhecexporter/testdata/hec_span_event.json b/exporter/splunkhecexporter/testdata/hec_span_event.json
new file mode 100644
index 0000000000000..dab1ab8094f90
--- /dev/null
+++ b/exporter/splunkhecexporter/testdata/hec_span_event.json
@@ -0,0 +1,20 @@
+{
+  "time": 1,
+  "host": "unknown",
+  "event": {
+    "trace_id": "01010101010101010101010101010101",
+    "span_id": "0000000000000001",
+    "parent_span_id": "0102030405060708",
+    "name": "root",
+    "end_time": 2000000000,
+    "kind": "SPAN_KIND_UNSPECIFIED",
+    "status": {
+      "message": "ok",
+      "code": "STATUS_CODE_OK"
+    },
+    "start_time": 1000000000
+  },
+  "fields": {
+    "resource": "R1"
+  }
+}