Optimizing APIs for Performance

When you expose data over the network, speed matters. Users expect sub‑second responses, especially on mobile. Below is a practical playbook to squeeze every ounce of performance out of your API.

1️⃣ Understand Latency Sources

Network RTT – Keep your API endpoints close to your users via regional endpoints or a CDN.
Server Processing – Profile your handlers; eliminate synchronous DB calls where possible.
Payload Size – Send only what the client needs. Use fields or projection parameters.

2️⃣ Reduce Payload Size

Compress JSON with gzip or brotli (set Accept-Encoding).
Use binary formats like Protocol Buffers if the client supports it.
Implement ETag & If-None-Match for caching immutable responses.

3️⃣ Leverage Caching Strategically

HTTP Caching – Set Cache-Control: public, max-age=86400 for static resources.
Distributed Cache – Redis or Memcached for expensive DB lookups.
Edge Caching – Put a reverse proxy (Varnish, Cloudflare) in front of your API.

4️⃣ Pagination & Streaming

Never return >200 records in one call. Use page + limit query params.
For large streams, return Chunked Transfer Encoding or server‑sent events.

5️⃣ Asynchronous & Non‑blocking I/O

Node.js, Go, and Rust all support async I/O. Offload blocking tasks to worker pools or message queues.

6️⃣ Load Balancing & Auto‑Scaling

Horizontal scaling across instances.
Health checks on /healthz endpoints.
Graceful draining during deployments.

7️⃣ Monitoring & Logging

Use OpenTelemetry or Prometheus for request tracing.
Instrument slow endpoints (>200ms) and alert on trends.

8️⃣ Versioning & Backward Compatibility

Use URL versioning (/v1/, /v2/) or Accept‑Header versioning so you can roll out new optimizations without breaking clients.

Putting these together means you’re not just serving data; you’re delivering a delightful experience.

Author: Soham Bharambe – Founder of Gen, creator of this little corner of the web where code meets community.

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