v4: the API's JSON and the page are sent compressed — a page of the feed went out as it was, twenty kilobytes where a fifth does: only the built frontend's files were compressed, at build time, and Deno's server leaves alone a response whose length Oak has set. compressMiddleware (api/middleware/compress.ts), installed after the error middleware and around everything that sets a body, sends an object or array, and a string whose type its route set, in brotli or gzip as the request's Accept-Encoding takes, a coding refused with q=0 not being taken, from a kilobyte up, the threshold the build compresses from. Brotli is at quality 5, the frontend's files, compressed once, staying at 11. Files, streams and bytes, a response already encoded, a HEAD and one marked no-transform go out as they are, and a compressible answer says Vary: Accept-Encoding whether compressed or not.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/main.ts

@@ -3,7 +3,8 @@
  * jobs and listens on {@link LISTEN_HOST}:{@link PORT}, having first signed
  * the users out of other instances if they may no longer sign in there
  * (`FEDERATION.outgoing`). A request goes
- * through the error middleware, the OG tags and CORS, then the routers, one
+ * through the error middleware, the compression of what is answered, the OG
+ * tags and CORS, then the routers, one
  * per resource of the API (`API.md` lists them), and last the built frontend,
  * which answers every path no router did.
  *
@@ -46,6 +47,7 @@ import {
   PORT,
   PUBLIC_URL,
 } from "./config.ts";
+import { compressMiddleware } from "./middleware/compress.ts";
 import { errorMiddleware } from "./middleware/error.ts";
 import { ogMiddleware } from "./middleware/og.ts";
 import { routeStaticFilesFrom } from "./lib/static.ts";
@@ -68,6 +70,7 @@ const app: Application = new Application();
 const cors = oakCors({ origin: ALLOWED_ORIGINS });
 
 app.use(errorMiddleware);
+app.use(compressMiddleware);
 app.use(ogMiddleware);
 // oakCors calls next() without awaiting it when there is no origin, which
 // corrupts the response in Oak's async chain. So it only sees requests from an