# HTTP headers that matter
URL: https://wwadd.dev/moves/git-http/http-headers

Caching and content negotiation live in headers. `Cache-Control` decides whether your CDN does any work at all.


```text
Content-Type: application/json
Accept: application/json
Authorization: Bearer <token>

Cache-Control: public, max-age=31536000, immutable   # hashed assets
Cache-Control: no-store                              # personal data
ETag / If-None-Match                                 # 304 revalidation

Access-Control-Allow-Origin: https://example.com     # CORS
Retry-After: 30                                      # with 429 / 503
```

## Related Moves
- [HTTP status codes worth memorizing](https://wwadd.dev/moves/git-http/status-codes)
- [REST basics](https://wwadd.dev/moves/git-http/rest-basics)