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4xx Series
Terminal (Do not automatically retry)

400 Bad Request

The server cannot or will not process the request due to an apparent client error (e.g., malformed request syntax).

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SEO Impact

Negative if encountered by crawlers. Indicates broken links leading to malformed URLs or invalid server configurations.

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Common Causes

  • 1Invalid JSON body
  • 2Missing required parameters
  • 3Malformed URI strings

Code Examples

Node.js (Express)
res.status(400).send('Missing email parameter');

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