diff --git a/relay/channel/openai/converter.go b/relay/channel/openai/converter.go
index 645959c..c42bcab 100644
--- a/relay/channel/openai/converter.go
+++ b/relay/channel/openai/converter.go
@@ -1369,11 +1369,9 @@ func HandleResponsesStreamToChat(ctx context.Context, resp *http.Response, info
 		if chunk == nil {
 			return true
 		}
-		data, err := json.Marshal(chunk)
-		if err != nil {
-			return false
-		}
-		return helper.WriteSSEData(writer, string(data)) == nil
+		// 池化缓冲 + 绑定 encoder：序列化与拼帧零分配，整帧单次写出。
+		// 序列化失败与写失败都返回 false（同旧行为），由调用方终止流。
+		return helper.WriteSSEDataJSON(writer, chunk) == nil
 	}
 
 	sendStartIfNeeded := func() bool {
diff --git a/relay/channel/openai/gemini_response.go b/relay/channel/openai/gemini_response.go
index 64729a1..f5b064a 100644
--- a/relay/channel/openai/gemini_response.go
+++ b/relay/channel/openai/gemini_response.go
@@ -157,8 +157,8 @@ func handleGeminiInboundStream(ctx context.Context, resp *http.Response, info *c
 		}
 
 		if len(geminiChunk.Candidates) > 0 {
-			chunkData, _ := json.Marshal(geminiChunk)
-			_ = helper.WriteSSEData(writer, string(chunkData))
+			// 传指针而非结构体值：值传进 any 会额外堆分配一份拷贝用于装箱
+			_ = helper.WriteSSEDataJSON(writer, &geminiChunk)
 		}
 	}
 
@@ -194,10 +194,9 @@ func handleGeminiInboundStream(ctx context.Context, resp *http.Response, info *c
 			finalChunk.UsageMetadata.ThoughtsTokenCount = usage.CompletionTokenDetails.ReasoningTokens
 		}
 	}
-	chunkData, _ := json.Marshal(finalChunk)
-	_ = helper.WriteSSEData(writer, string(chunkData))
+	_ = helper.WriteSSEDataJSON(writer, &finalChunk)
 
-	helper.WriteSSEData(writer, "[DONE]")
+	_ = helper.WriteSSEData(writer, "[DONE]")
 	info.StreamStatus.SetEndReason(common.StreamEndReasonDone, nil)
 
 	if err := scanner.Err(); err != nil && err != io.EOF && ctx.Err() == nil {
diff --git a/relay/channel/openai/pooled_sse_stream_test.go b/relay/channel/openai/pooled_sse_stream_test.go
new file mode 100644
index 0000000..36d02bc
--- /dev/null
+++ b/relay/channel/openai/pooled_sse_stream_test.go
@@ -0,0 +1,211 @@
+package openai
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/qianfree/team-api/relay/common"
+	"github.com/qianfree/team-api/relay/constant"
+	"github.com/qianfree/team-api/relay/dto"
+)
+
+// 本文件覆盖两条改用池化帧写入器（helper.WriteSSEDataJSON）的转换路径：
+//   - handleGeminiInboundStream：OpenAI 上游 → Gemini 客户端
+//   - HandleResponsesStreamToChat：Responses 上游 → Chat Completions 客户端
+//
+// 两条路径此前无测试覆盖。断言两件事：
+//  1. 输出仍是合法且内容正确的 SSE（池化不能改变对外协议）；
+//  2. 每次 Write 都落在帧边界（整帧单次写出，并发保活 ping 插不进帧中间）。
+
+// assertFramesAreSingleWrites 断言每次 Write 都是一个以空行收尾的完整帧
+func assertFramesAreSingleWrites(t *testing.T, chunks []string) {
+	t.Helper()
+	if len(chunks) == 0 {
+		t.Fatal("没有任何写出")
+	}
+	for i, c := range chunks {
+		if !strings.HasSuffix(c, "\n\n") {
+			t.Errorf("第 %d 次 Write 未落在帧边界，保活 ping 可插入其中:\n%q", i, c)
+		}
+	}
+}
+
+// collectSSEDataFrames 从 SSE 文本中取出所有 data 行的内容
+func collectSSEDataFrames(raw string) []string {
+	var out []string
+	for _, line := range strings.Split(raw, "\n") {
+		line = strings.TrimSuffix(line, "\r")
+		if strings.HasPrefix(line, "data:") {
+			out = append(out, strings.TrimSpace(strings.TrimPrefix(line, "data:")))
+		}
+	}
+	return out
+}
+
+func geminiInboundInfo() *common.RelayInfo {
+	return &common.RelayInfo{
+		IsStream:        true,
+		InboundFormat:   constant.RelayFormatGemini,
+		ClientFormat:    constant.RelayFormatGemini,
+		OriginModelName: "gemini-3-pro",
+		StreamStatus:    common.NewStreamStatus(),
+		ChannelMeta: &common.ChannelMeta{
+			ChannelType:       int(constant.ProviderOpenAI),
+			BaseURL:           "https://upstream.example.com",
+			UpstreamModelName: "gpt-4o",
+		},
+	}
+}
+
+// TestHandleGeminiInboundStream_PooledFramesValid OpenAI SSE → Gemini SSE：
+// 每个 chunk 都是完整可解析的 Gemini JSON，且整帧单次写出。
+func TestHandleGeminiInboundStream_PooledFramesValid(t *testing.T) {
+	upstream := strings.Join([]string{
+		`data: {"id":"c1","object":"chat.completion.chunk","choices":[{"index":0,"delta":{"role":"assistant","content":"你好"}}]}`,
+		``,
+		`data: {"id":"c1","object":"chat.completion.chunk","choices":[{"index":0,"delta":{"content":"世界"}}]}`,
+		``,
+		`data: {"id":"c1","object":"chat.completion.chunk","choices":[{"index":0,"delta":{},"finish_reason":"stop"}],"usage":{"prompt_tokens":11,"completion_tokens":7,"total_tokens":18}}`,
+		``,
+		`data: [DONE]`,
+		``,
+	}, "\n")
+
+	resp := &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": {"text/event-stream"}},
+		Body:       io.NopCloser(strings.NewReader(upstream)),
+	}
+
+	info := geminiInboundInfo()
+	rec := &sseFrameRecorder{}
+
+	usage, err := handleGeminiInboundStream(context.Background(), resp, info, rec)
+	if err != nil {
+		t.Fatalf("handleGeminiInboundStream error: %v", err)
+	}
+
+	assertFramesAreSingleWrites(t, rec.chunks)
+
+	frames := collectSSEDataFrames(rec.body.String())
+	if len(frames) < 2 {
+		t.Fatalf("data 帧数 = %d, 期望至少 2（内容 chunk + 终止 chunk）\n%s", len(frames), rec.body.String())
+	}
+
+	var text strings.Builder
+	sawDone := false
+	for i, f := range frames {
+		if f == "[DONE]" {
+			sawDone = true
+			if i != len(frames)-1 {
+				t.Errorf("[DONE] 不在最后一帧（位置 %d/%d）", i, len(frames)-1)
+			}
+			continue
+		}
+		var chunk dto.GeminiChatResponse
+		if err := json.Unmarshal([]byte(f), &chunk); err != nil {
+			t.Fatalf("第 %d 帧不是合法 Gemini JSON（池化若出错会产生这种残片）: %v\ndata=%q", i, err, f)
+		}
+		for _, cand := range chunk.Candidates {
+			if cand.Content == nil {
+				continue
+			}
+			for _, p := range cand.Content.Parts {
+				text.WriteString(p.Text)
+			}
+		}
+	}
+	if !sawDone {
+		t.Error("缺少 [DONE] 终止帧")
+	}
+	if got := text.String(); got != "你好世界" {
+		t.Errorf("转发文本 = %q, want %q", got, "你好世界")
+	}
+	if usage == nil || usage.PromptTokens != 11 || usage.CompletionTokens != 7 {
+		t.Errorf("usage = %+v, want prompt=11 completion=7", usage)
+	}
+}
+
+func responsesToChatInfo() *common.RelayInfo {
+	return &common.RelayInfo{
+		IsStream:        true,
+		InboundFormat:   constant.RelayFormatOpenAI,
+		ClientFormat:    constant.RelayFormatOpenAI,
+		OriginModelName: "gpt-4o",
+		StreamStatus:    common.NewStreamStatus(),
+		ChannelMeta: &common.ChannelMeta{
+			ChannelType:       int(constant.ProviderOpenAI),
+			BaseURL:           "https://upstream.example.com",
+			UpstreamModelName: "gpt-4o",
+			SupportsResponses: true,
+		},
+	}
+}
+
+// TestHandleResponsesStreamToChat_PooledFramesValid Responses SSE → Chat SSE：
+// 每个 chunk 都是完整可解析的 chat.completion.chunk，且整帧单次写出。
+func TestHandleResponsesStreamToChat_PooledFramesValid(t *testing.T) {
+	upstream := strings.Join([]string{
+		"event: response.created",
+		`data: {"type":"response.created","response":{"id":"resp_1","object":"response","status":"in_progress"}}`,
+		``,
+		"event: response.output_text.delta",
+		`data: {"type":"response.output_text.delta","delta":"你好"}`,
+		``,
+		"event: response.output_text.delta",
+		`data: {"type":"response.output_text.delta","delta":"世界"}`,
+		``,
+		"event: response.completed",
+		`data: {"type":"response.completed","response":{"id":"resp_1","object":"response","status":"completed","usage":{"input_tokens":11,"output_tokens":7,"total_tokens":18}}}`,
+		``,
+		`data: [DONE]`,
+		``,
+	}, "\n")
+
+	resp := &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": {"text/event-stream"}},
+		Body:       io.NopCloser(strings.NewReader(upstream)),
+	}
+
+	info := responsesToChatInfo()
+	rec := &sseFrameRecorder{}
+
+	if _, err := HandleResponsesStreamToChat(context.Background(), resp, info, rec); err != nil {
+		t.Fatalf("HandleResponsesStreamToChat error: %v", err)
+	}
+
+	assertFramesAreSingleWrites(t, rec.chunks)
+
+	frames := collectSSEDataFrames(rec.body.String())
+	var text strings.Builder
+	sawDone := false
+	for i, f := range frames {
+		if f == "[DONE]" {
+			sawDone = true
+			continue
+		}
+		var chunk dto.ChatCompletionStreamResponse
+		if err := json.Unmarshal([]byte(f), &chunk); err != nil {
+			t.Fatalf("第 %d 帧不是合法 chat.completion.chunk: %v\ndata=%q", i, err, f)
+		}
+		if chunk.Object != "chat.completion.chunk" {
+			t.Errorf("第 %d 帧 object = %q, want chat.completion.chunk", i, chunk.Object)
+		}
+		for _, c := range chunk.Choices {
+			if s, ok := c.Delta.Content.(string); ok {
+				text.WriteString(s)
+			}
+		}
+	}
+	if !sawDone {
+		t.Error("缺少 [DONE] 终止帧")
+	}
+	if got := text.String(); got != "你好世界" {
+		t.Errorf("转发文本 = %q, want %q", got, "你好世界")
+	}
+}
diff --git a/relay/helper/stream_test.go b/relay/helper/stream_test.go
index 7b36b13..de87706 100644
--- a/relay/helper/stream_test.go
+++ b/relay/helper/stream_test.go
@@ -832,6 +832,33 @@ func TestWriteSSEEventJSON_RealWorldFrameSizes(t *testing.T) {
 	}
 }
 
+// BenchmarkSSEData_PooledJSON_Pointer / _Value 验证「传指针而非结构体值」的理由：
+// 结构体值传进 any 形参需要装箱，会额外堆分配一份拷贝；传指针则不会。
+// 迁移调用点时据此统一传 &chunk。
+func BenchmarkSSEData_PooledJSON_Pointer(b *testing.B) {
+	w := &discardWriter{}
+	payload := benchClaudeDelta() // 已是指针
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		if err := WriteSSEDataJSON(w, payload); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func BenchmarkSSEData_PooledJSON_Value(b *testing.B) {
+	w := &discardWriter{}
+	payload := *benchClaudeDelta() // 解引用成值
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		if err := WriteSSEDataJSON(w, payload); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
 // TestSSEFrameWriter_MaxBufDegradeSuppressesPing 超大帧降级为分次写出时，写出的这批字节
 // 不含帧尾 —— 此刻放行 ping 依然会把帧劈成两个事件。降级期间必须抑制 ping，直到分隔空行到达。
 func TestSSEFrameWriter_MaxBufDegradeSuppressesPing(t *testing.T) {