Articles/HTTP

HTTP 304 Not Modified — What It Means

What HTTP status code 304 Not Modified means, when servers return it, and how to handle it correctly.

Published September 23, 2026

HTTP 304 Not Modified — The client's cached version of the resource is still valid — no new content is being sent.

Key points

  • Returned when a conditional GET request's If-None-Match or If-Modified-Since header matches the current version
  • Has no response body, saving bandwidth since the client already holds a valid cached copy
  • Relies on ETag or Last-Modified headers set on a previous response
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