HTTP compression utility

Accept-Encoding Header Builder & Compression Negotiation Tester

Build clean Accept-Encoding headers, tune q-values, simulate how a server will choose between Brotli, gzip, zstd, identity, and wildcard fallbacks, and copy deployment snippets without hunting through RFC notes.

Supports br, gzip, deflate, zstd, identity, *
Useful for APIs, CDNs, app servers
Includes Negotiation preview + snippets
Output Header, curl, Nginx, Express

1) Client header

Choose the encodings your client advertises. Lower q-values mean lower preference. A q-value of 0 explicitly rejects that encoding.

2) Negotiation tester

Simulate a server choosing an encoding based on your advertised preferences, the server's available codecs, and whether compression is worthwhile for the response size.

Generated Accept-Encoding header

Advertised codecs0
Top preference
Identity allowedYes

Negotiation result

Waiting for simulation
Selected encoding
Estimated transfer size
Estimated savings

Compatibility matrix

Quick directional guidance. Actual support depends on the client, transport stack, and server implementation.

Rule of thumb: Brotli usually wins for web text assets, gzip remains the broad compatibility baseline, zstd is promising but not universal in browser request headers yet, and identity is the no-compression fallback.

Copyable snippets

Implementation notes