Response compression (only when it helps)

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                  import compression from 'compression';
import type { Express } from 'express';

export function applyCompression(app: Express) {
  app.use(
    compression({
      threshold: 1024,
      filter: (req, res) => {
        if (req.path.startsWith('/events')) return false;
        return compression.filter(req, res);
      }
    })
  );
}

Compression can dramatically reduce payload sizes for JSON and HTML, but it also costs CPU. I enable it with sane defaults and avoid compressing already-compressed content (like images). Compression can also hurt streaming responses and SSE, so I disable it for event streams. I set a minimum threshold so tiny responses don’t pay overhead. The goal isn’t ‘compress everything’; it’s ‘compress where it’s an obvious win’. This is an easy change to measure: compare transfer size and response times before and after.

Mateo Rodriguez

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Response compression (only when it helps)

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