What does HTTP status 529 (Site Overloaded) mean?

HTTP_STATUS_SITE_OVERLOADED

The status is not registered by IANA. The SSL Labs API documentation uses 529 for a temporary service-overload condition and recommends retrying later rather than treating it as a permanent client error.

Use exponential backoff with a cap and avoid synchronized retries. The exact retry policy must follow the emitting service documentation because 529 has no universal HTTP semantics.

SSL Labs API documentation

Operational meaning of HTTP 529 for HTTP_STATUS_SITE_OVERLOADED

HTTP 529 (this result) is a server-error response. AllStat records its meaning as “529 Site is overloaded”. Interpret it with the request method, selected representation, response headers, and the specification or product that defines the code; the number alone does not prove that application work completed.

Client and server handling

• Correlate this result with origin, gateway, load-balancer, and dependency logs to locate which hop generated it.
• record request and trace identifiers, upstream timing, retry count, and the health of the selected backend.
• use bounded retries with backoff only for idempotent work and only when the service policy permits them.

For telemetry, record HTTP 529, method, authority, route template rather than secrets, response headers relevant to caching or retry, latency, upstream identity, and whether the response originated at the application or an intermediary.

Looking for a different code? Search another status or error code.