Redirect (3xx)

HTTP 304 Not Modified

The cached version of the resource is still valid. No content is transferred.

304

Not Modified

The cached version of the resource is still valid. No content is transferred.

What Causes HTTP 304?

Client sent If-Modified-Since or If-None-Match headers
Resource has not changed since the last request
Browser cache validation
Conditional GET request

Code Examples

See how HTTP 304 responses look in different programming languages and tools.

curl -I -H "If-Modified-Since: Wed, 01 Jan 2026 00:00:00 GMT" \
  https://api.example.com/resource
# Response: 304 Not Modified (empty body)

How to Fix HTTP 304

Use cached version of the resource
No data transfer needed — saves bandwidth
Verify caching headers are properly configured

Related Status Codes

200OK

The request was successful. The response body contains the requested resource.

301Moved Permanently

The resource has been permanently moved to a new URL. All future requests should use the new URL.

400Bad Request

The request was malformed or invalid. The server cannot process it.

Test Your APIs

API Response Time Checker

Test your API endpoints and see exactly which status codes they return

API Uptime Monitor

Monitor your API for errors and track status code distributions

Frequently Asked Questions

What does HTTP 304 mean?

The cached version of the resource is still valid. No content is transferred.

What causes HTTP 304?

Client sent If-Modified-Since or If-None-Match headers. Resource has not changed since the last request. Browser cache validation. Conditional GET request

How to fix HTTP 304?

Use cached version of the resource. No data transfer needed — saves bandwidth. Verify caching headers are properly configured

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