From d707105053642d6ae005c68b616bc1a5581c2d84 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebasti=C3=A1n=20Ram=C3=ADrez?= <tiangolo@gmail.com>
Date: Sun, 1 Mar 2026 09:16:15 +0100
Subject: [PATCH] =?UTF-8?q?=E2=99=BB=EF=B8=8F=20Refactor=20ServerSentEvent?=
 =?UTF-8?q?=20to=20use=20id:=20str?=
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---
 fastapi/sse.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fastapi/sse.py b/fastapi/sse.py
index bd14713617..901d824964 100644
--- a/fastapi/sse.py
+++ b/fastapi/sse.py
@@ -33,8 +33,8 @@ class EventSourceResponse(StreamingResponse):
     media_type = "text/event-stream"
 
 
-def _check_id_no_null(v: int | str | None) -> int | str | None:
-    if v is not None and "\0" in str(v):
+def _check_id_no_null(v: str | None) -> str | None:
+    if v is not None and "\0" in v:
         raise ValueError("SSE 'id' must not contain null characters")
     return v
 
@@ -96,7 +96,7 @@ class ServerSentEvent(BaseModel):
         ),
     ] = None
     id: Annotated[
-        int | str | None,
+        str | None,
         AfterValidator(_check_id_no_null),
         Doc(
             """
@@ -162,7 +162,7 @@ def format_sse_event(
         ),
     ] = None,
     id: Annotated[
-        int | str | None,
+        str | None,
         Doc(
             """
             Optional event ID (`id:` field).