intermediate

HTTP and Networking

Understand transport basics, DNS, TLS, HTTP versions, browser networking constraints, proxies, load balancers, and gateways.

HTTP and networking interviews require transport literacy: DNS, TLS, HTTP versions, browser constraints, proxies, load balancers, and gateways—not just framework route handlers.

Child sections: networking basics, HTTP protocol, browser networking, and proxies and gateways.

On interviews: explain why HTTPS failed after a cert rotation, how HTTP/2 changes connection behavior, and where CORS is enforced.

Common pitfalls: debugging only application code while DNS or TLS is wrong, ignoring keep-alive and socket exhaustion, and treating the browser as a generic HTTP client.

The trade-off is balancing simplicity, performance, safety, and operability — name which axis you optimized and what cost you accepted.

Checklist:

Trace DNS → TCP/TLS → HTTP on critical paths.
Know method, status, header, and caching semantics.
Separate server-side networking from browser CORS rules.
Place proxies and gateways with clear trust boundaries.