HTTP Status Code 412

The status code 412, also known as "Precondition Failed", is an error code used in communication between web servers and clients (like web browsers) based on the HTTP protocol. It indicates that a specific condition set by the client in a request has not been met by the server.

These conditions are typically specified using special headers within the request, and they allow the client to control how the server responds to the request. For instance, a client might ask the server to only update a resource if it hasn't been modified since a certain date. If the server finds that the resource has already been changed, it would respond with a 412 error code.

This code is mainly used with requests that modify data on the server (like PUT or DELETE) rather than simply retrieving data (GET).

Other 4xx Status Codes

• 400 Bad Request
• 401 Unauthorized
• 402 Payment Required
• 403 Forbidden
• 404 Not Found
• 405 Method Not Allowed
• 406 Not Acceptable
• 407 Proxy Authentication Required
• 408 Request Timeout
• 409 Conflict
• 410 Gone
• 411 Length Required
• 412 Precondition Failed
• 413 Payload Too Large
• 414 URI Too Long
• 415 Unsupported Media Type
• 416 Range Not Satisfiable
• 417 Expectation Failed
• 418 I'm a teapot
• 421 Misdirected Request
• 422 Unprocessable Entity
• 423 Locked
• 424 Failed Dependency
• 425 Too Early
• 426 Upgrade Required
• 428 Precondition Required
• 429 Too Many Requests
• 431 Request Header Fields Too Large
• 451 Unavailable For Legal Reasons