What Is HTTP 304 Not Modified?
HTTP 304 Not Modified explained, and what it means when you see it in CI/CD and deployments.
HTTP 304 tells the client its cached version is current, so no body is sent.
What it means
A 304 is returned when a conditional request (If-None-Match/If-Modified-Since) matches the server state. It saves bandwidth by reusing the cached response.
When you see it in CI/CD
CI dependency caches rely on conditional requests; a 304 means a cached artifact is reused instead of re-downloaded, speeding up the build.
Key takeaways
- 304 means use your cached copy.
- Triggered by conditional requests.
- Saves CI download bandwidth.