Enable compression

boatramp negotiates compression per request from the client’s Accept-Encoding. Precompressed sibling variants are preferred over on-the-fly compression because they cost no per-request CPU. This page covers both. For how compression interacts with Cache-Control and ETag, see Control caching.

Ship precompressed variants

At sync, boatramp compresses compressible files and stores br and gzip blobs next to the identity blob — an app.js gets app.js.br and app.js.gz siblings. A variant is kept only when it is smaller than identity.

At serve time boatramp negotiates Accept-Encoding (brotli over gzip, honoring ;q=0 and *), returns the best variant the client accepts, and sets Content-Encoding, a per-representation ETag, and Vary: Accept-Encoding.

Request the brotli variant:

curl -sI -H 'Accept-Encoding: br' https://my-site.example/app.js

HTTP/2 200
content-type: text/javascript
content-encoding: br
vary: accept-encoding

A client sending no Accept-Encoding — or identity — gets the uncompressed blob and the same Vary header.

Compress on the fly

Responses with no precompressed variant — dynamic handler and proxy output — can be compressed per request. Build with the compression feature and enable it in the site’s config:

// site access/compression config
compression: ( enabled: true, min_size: 1024 ),

boatramp streams a gzip or brotli encoder over compressible responses at least min_size bytes. It skips Set-Cookie responses for BREACH safety, and Range requests always serve identity. Where a precompressed variant exists it still wins — on-the-fly compression only fills the gap.