SteadyNode

Heroku / Render · HTTP 502

Render 502: Web Service Not Responding

Investigate Render 502 responses by checking deploy and runtime logs, the configured start command, port binding, and service health-check path.

Origin / Network Firewall

Decode a CDN or gateway error

Paste a captured HTTP response or enter a status and headers. Only the status and response headers are sent; common credential headers are filtered first.

Supports raw headers, full HTTP responses, JSON with status/statusCode and headers, cURL -v/-i response output, and HAR exports. HAR selects a server error first. cURL commands are never executed; request headers, response bodies, and common credential headers are excluded.

Diagnostic report

Error code / name

RENDER-502-BAD_GATEWAY

Fault domain

Origin / Network Firewall

Why it happened

The platform could not obtain a valid response from the web service. A failed deploy, process restart, incorrect port binding, or startup failure can leave the proxy without a healthy application.

Actionable fixes

  1. Inspect deploy and runtime logs for the first startup error and confirm the service stays running.
  2. Bind the application to the platform-provided PORT on the expected interface.
  3. Set a health-check path that returns success only after the web process is ready to serve requests.

Why this error happened

The platform could not obtain a valid response from the web service. A failed deploy, process restart, incorrect port binding, or startup failure can leave the proxy without a healthy application.

Actionable fixes

  1. Inspect deploy and runtime logs for the first startup error and confirm the service stays running.
  2. Bind the application to the platform-provided PORT on the expected interface.
  3. Set a health-check path that returns success only after the web process is ready to serve requests.

Network failure point

Client -> Render Proxy -> service process starts or binds wrong port -> no upstream response -> X

Verify origin directly via CLI

curl -sS -I -v --max-time 20 https://example.onrender.com/health

Configuration fix

render.yamlyaml
services:
  - type: web
    name: api
    runtime: node
    buildCommand: npm ci && npm run build
    startCommand: npm start
    healthCheckPath: /health/ready

Catch this failure before it becomes an outage

SteadyNode's external checks detect public 502 responses independently of deploy health panels and show whether the service recovered after a restart or release.

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Frequently asked questions

Can binding to the wrong port cause a Render 502?

Yes. The service must listen on the platform-provided port and remain running for the proxy to reach it.

What should a service health-check path return?

Return a successful status when the process is ready to serve. Do not report ready before required initialization finishes.

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