Errors

Interpret FOSSA API error responses, 4xx codes indicate client errors, 5xx codes indicate server-side issues.

1 min readUpdated Jul 9, 2026

Overview

The FOSSA API uses conventional HTTP response codes to indicate the success or failure of a request.

Status rangeMeaningWhat to do
2xxSuccessThe request succeeded.
4xxClient errorSomething about the request was wrong, for example, a missing API token or an omitted required parameter. Check your request and try again.
5xxServer errorAn error occurred on FOSSA's servers. Retry later, and contact support if it persists.

For the full list of HTTP status codes, see List of HTTP status codes.

Note

If you receive an unexpected error, contact support@fossa.com with the endpoint, request, and response you received.

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