From e6ccaec2fe07d822f402cacf404e03397cef0bbc Mon Sep 17 00:00:00 2001
From: saravanakumardb1 <saravanakumardb1@users.noreply.github.com>
Date: Sun, 29 Mar 2026 12:47:13 -0700
Subject: [PATCH] fix(fastify-sse): add X-Accel-Buffering header to per-request
 startSSE

Aligns with hub.ts which already includes this header. Prevents
nginx/Traefik from buffering SSE chunks behind a reverse proxy.
---
 packages/fastify-sse/src/per-request.test.ts | 1 +
 packages/fastify-sse/src/per-request.ts      | 1 +
 2 files changed, 2 insertions(+)

diff --git a/packages/fastify-sse/src/per-request.test.ts b/packages/fastify-sse/src/per-request.test.ts
index de5cb632..ca21f88b 100644
--- a/packages/fastify-sse/src/per-request.test.ts
+++ b/packages/fastify-sse/src/per-request.test.ts
@@ -27,6 +27,7 @@ describe('per-request SSE helpers', () => {
         'Content-Type': 'text/event-stream',
         'Cache-Control': 'no-cache',
         Connection: 'keep-alive',
+        'X-Accel-Buffering': 'no',
       });
     });
 
diff --git a/packages/fastify-sse/src/per-request.ts b/packages/fastify-sse/src/per-request.ts
index 216bd10d..d1c8dc7f 100644
--- a/packages/fastify-sse/src/per-request.ts
+++ b/packages/fastify-sse/src/per-request.ts
@@ -11,6 +11,7 @@ export function startSSE(reply: FastifyReply): void {
     'Content-Type': 'text/event-stream',
     'Cache-Control': 'no-cache',
     Connection: 'keep-alive',
+    'X-Accel-Buffering': 'no',
   });
   reply.hijack();
 }