index.md

---
title: 400 Bad Request
slug: Web/HTTP/Status/400
page-type: http-status-code
spec-urls: https://httpwg.org/specs/rfc9110.html#status.400
---

{{HTTPSidebar}}

The HyperText Transfer Protocol (HTTP) **`400 Bad Request`** response status code indicates that the server cannot or will not process the request due to something that is perceived to be a client error (for example, malformed request syntax, invalid request message framing, or deceptive request routing).

> **Warning:** The client should not repeat this request without modification.

## Status

```http
400 Bad Request
```

## Specifications

{{Specifications}}

## See also

- [HTTP Status Code Definitions](https://httpwg.org/specs/rfc9110.html#status.400)