status Registered
Verified 2026-09-18 · registry updated 2025-09-15

HTTP 503 Service Unavailable

The server is temporarily unable to handle the request.

Use 503 during overload, maintenance, or dependency outages and provide Retry-After when appropriate.

httpstatus codeserver errorretry

Response (http)

HTTP/1.1 503 Service Unavailable

Use 503 during overload, maintenance, or dependency outages and provide Retry-After when appropriate.

Common mistakes

  • Serving 503 without Retry-After, or using it to paper over permanent failures.

Registry reference: RFC9110, Section 15.6.4

Sources

Permalink: https://merginit.com/reference/http/status-503