Why should you care?

Angular makes many parallel calls — slow APIs multiply into frozen UI.

See it live — copy this example

Paste into your MeanVerse project (Angular + Express + MongoDB), then run with ng serve / node / mongosh as noted.

import compression from 'compression';

app.use(compression());
app.get('/api/v1/accounts', auth, async (req, res) => {
  const page = Math.max(1, Number(req.query.page) || 1);
  const limit = Math.min(100, Number(req.query.limit) || 20);
  const filter = { tenantId: req.user.tenantId };
  const [items, total] = await Promise.all([
    Account.find(filter).select('name balanceCents').skip((page - 1) * limit).limit(limit).lean(),
    Account.countDocuments(filter)
  ]);
  res.set('Cache-Control', 'private, max-age=10');
  res.json({ items, total, page, limit });
});

What happened?

• compression gzip JSON bodies.
• Parallel find + count with Promise.all.
• select + lean minimizes payload.
• Cache-Control hints browser/CDN for brief private cache.

Practice next

1. Add compression middleware globally.
2. Paginate all list endpoints with max limit cap.
3. Return ETag for conditional GET on static config.
4. Add cursor-based pagination for infinite scroll.
5. Enable HTTP/2 behind Nginx for multiplexing.

Remember

Compress, paginate, project, parallelize. Set cache headers where safe. Measure p95 with APM tools.

Mobile account list

App scrolled infinite list; offset pagination slow at page 500.

Outcome: Cursor pagination by _id keeps constant time per page.