Full Stack developer interview questions

HTTPS encrypts traffic so attackers on the network cannot read tokens or form data.

A WebSocket is a persistent two-way connection after an HTTP upgrade.

Use WebSockets when the client must receive updates immediately without polling.

Caching stores expensive results so the next request is faster.

Browser caching uses HTTP headers such as Cache-Control to reuse static assets.

Continuous Integration automatically builds and tests every change.

PR checks catch broken builds before they reach main.

nginx is a reverse proxy and static file server.

A .env file holds local configuration such as PORT, MONGO_URI, and JWT_SECRET.

NODE_ENV tells libraries whether the process is development, test, or production.

Git marks overlapping edits in the file with conflict markers.

git stash temporarily shelves uncommitted work so you can switch branches cleanly.

git restore discards or unstages working tree changes.

A remote is a named URL Git pulls from and pushes to

An idempotent method can be repeated with the same effect as calling it once.

Content-Type describes the body you are sending, such as application/json.

For non-simple cross-origin calls, the browser first sends an OPTIONS request asking if the real method, headers, and origin are allowed.

The server sends Set-Cookie

Keep-alive reuses a TCP connection for multiple HTTP requests instead of opening a new one each time.

Callbacks pass errors as the first argument and nest easily into callback hell.