SIP
502 Bad Gateway レスポンスのモック
The server, acting as a gateway or proxy, received an invalid response from a downstream server it accessed in attempting to fulfill the request.
完全なリファレンスを見る →1 HTTP レスポンス
HTTP/1.1 502 Bad Gateway
Content-Type: application/json
Date: Tue, 25 Feb 2026 12:00:00 GMT
Content-Length: 60
{
"error": "bad_gateway",
"message": "Upstream server error"
}
2 curl でテストする
curl -i https://httpbin.org/status/502
3 フレームワークで 502 Bad Gateway を返す
django
from django.http import JsonResponse
def my_view(request):
return JsonResponse(
{"error": "bad_gateway", "message": "Upstream server error"},
status=502,
)
flask
from flask import Flask, jsonify
app = Flask(__name__)
@app.route("/endpoint")
def my_endpoint():
return jsonify({"error": "bad_gateway", "message": "Upstream server error"}), 502
fastapi
from fastapi import FastAPI
from fastapi.responses import JSONResponse
app = FastAPI()
@app.get("/endpoint")
def my_endpoint():
return JSONResponse(
content={"error": "bad_gateway", "message": "Upstream server error"},
status_code=502,
)
express.js
// Express.js
app.get('/endpoint', (req, res) => {
res.status(502).json({"error": "bad_gateway", "message": "Upstream server error"});
});
spring boot
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import java.util.Map;
@RestController
public class MyController {
@GetMapping("/endpoint")
public ResponseEntity<Map<String, Object>> myEndpoint() {
return ResponseEntity
.status(502)
.body(Map.of("error", "bad_gateway",
"message", "Bad Gateway"));
}
}
go net/http
package main
import (
"encoding/json"
"net/http"
)
func myHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(502)
json.NewEncoder(w).Encode(map[string]string{
"error": "bad_gateway",
"message": "Bad Gateway",
})
}
ruby on rails
class MyController < ApplicationController
def my_action
render json: {"error": "bad_gateway", "message": "Upstream server error"},
status: :bad_gateway
end
end
asp.net core
// ASP.NET Core Minimal API
app.MapGet("/endpoint", () =>
Results.Json(
new { error = "bad_gateway", message = "Bad Gateway" },
statusCode: 502
)
);