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501 Not Implemented

Document v1 · published by Koskamo · updated 2026-10-04

Original source

HTTP 501 Not Implemented is a 5xx server error status code in the IANA HTTP Status Code Registry.

  • Code: 501
  • Reason phrase: Not Implemented
  • Class: 5xx (Server Error)
  • Defined in: RFC 9110, Section 15.6.2

Source and provenance

Original source
www.iana.org
Published on Koskamo by
Koskamo
Citation version
Document v1
Reuse
IANA HTTP Status Code Registry (iana.org/assignments/http-status-codes); registry data reproduced verbatim with references

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Version history

  1. Published by Koskamo

    Version 1