400 Bad Request

Meaning

The request is malformed or uses an invalid structure, so the server refuses to process it.

Causes

• Invalid parameters or body
• Missing required headers
• Incorrect URL or routing

How to fix

• Fix request format according to docs
• Add required headers
• Verify the URL/route

Example

HTTP/1.1 400 Bad Request

Official references

IANA HTTP Status Code RegistryOfficialRegistryhttps://www.iana.org/assignments/http-status-codesOpen in new tab MDN HTTP response status codesReferenceDocshttps://developer.mozilla.org/en-US/docs/Web/HTTP/StatusOpen in new tab RFC 9110 (HTTP Semantics)ReferenceSpechttps://www.rfc-editor.org/rfc/rfc9110Open in new tab RFC 9110: 400 status codeReferenceSpechttps://www.rfc-editor.org/rfc/rfc9110Open in new tab

FAQ

• Is it my problem or the server’s? — It’s usually a client-side request formatting issue.
• What should I check first? — Validate parameters, headers, and body structure.

When to contact support

If it persists, contact the API provider or site admin to check request logs.