APITester| Status code | 509 |
|---|---|
| Status text | Bandwidth Limit Exceeded |
| Category | 5xx Server Error |
| Response has body | Usually |
| Defined by | Hosting control panels (not an IANA-registered code) |
What does 509 Bandwidth Limit Exceeded mean?
The site has used up the data transfer its hosting plan allows. It is numbered in the 5xx Server Error range but is not a registered HTTP status code, so the general meaning of that class is only a rough guide to it.
When do APIs return 509?
On shared hosting, where a control panel enforces a monthly bandwidth quota per account and serves this error to every visitor once it is spent. A traffic spike, large downloads, images hot-linked from other sites and aggressive crawlers are the usual ways a quota runs out early.
How to fix a 509 Bandwidth Limit Exceeded
As a visitor, there is nothing to do but come back later. As the site owner, the limit resets at the start of the next billing period, or sooner if you raise it or upgrade the plan. To stop it recurring, find what consumed the transfer in the hosting panel's statistics, put a CDN in front of static files, and block hot-linking. An API you design yourself should use 429 for a caller over quota, not this code.
Reproduce a 509 response
The fastest way to understand a status code is to trigger one and read the full response. Open the
API tester and send a request to https://httpbin.org/status/509 — you will
see the 509 status along with every response header the server sent. Comparing those headers against
a working request is often what reveals the cause.
That response only imitates the number, which is useful for checking how your own client, alerting or retry logic treats a 509. A real one comes from the software named in the table above, in the circumstances this page describes.
When you are debugging a real endpoint, check the response headers as carefully as the body, and confirm you are using the right HTTP method for the operation.
Related 5xx status codes
500 Internal Server Error
The server hit an unexpected condition and could not complete the request.
501 Not Implemented
The server does not support the functionality required to fulfil the request.
502 Bad Gateway
A server acting as a gateway or proxy received an invalid response from the upstream server.
503 Service Unavailable
The server is temporarily unable to handle the request.
504 Gateway Timeout
A gateway or proxy did not receive a timely response from the upstream server.
505 HTTP Version Not Supported
The server does not support the major HTTP version named in the request.
See also
- 429 Too Many Requests — You have sent too many requests in a given amount of time and are being rate limited.
- 503 Service Unavailable — The server is temporarily unable to handle the request.
References
- IANA: HTTP Status Code Registry — The official list of registered codes. This one is not on it.