Compression

Easel compresses eligible static files and function responses automatically. You don't need to compress HTML, JSON, JavaScript, or CSS in your code.

Encoding

Easel reads the request's Accept-Encoding, prefers Brotli (br), and falls back to gzip. A client that advertises neither gets the uncompressed body. Compressed responses carry Content-Encoding and Vary: Accept-Encoding.

Cached responses are stored already compressed, one copy per encoding, so a cache hit isn't compressed again. See Caching.

What isn't compressed

• Responses that already have Content-Encoding. Easel passes them through unchanged.
• Very small responses, where headers outweigh the savings.
• Already-compressed formats, such as JPEG, PNG, WebP, AVIF, video, audio, and archives.
• Responses with a missing or non-text Content-Type.
• Range requests.

Precompressed responses

Set Content-Encoding only when the body is actually encoded. Declaring gzip or br on a plain body makes clients fail to decode it. Don't compress in your app and also let a framework or proxy compress the same response.

Streaming

Streamed responses are compressed as they're sent. Compression can hold back small chunks until there's enough to encode, which can delay Server-Sent Events or other latency-sensitive streams. Test those routes on a preview deployment.

Verify

curl -sI -H "Accept-Encoding: br, gzip" https://example.com/app.js

Look for Content-Encoding: br. Send Accept-Encoding: identity to compare the uncompressed response. If compression is missing, see CDN troubleshooting.