Full Stack developer interview questions

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.

Streams process data in chunks instead of loading an entire file or response into memory.

Wrap awaited calls in try/catch or use a wrapper that forwards rejections to next.

process.nextTick queues a callback to run after the current operation, before the event loop continues.

cluster forks worker processes so a multi-core machine can handle more concurrent connections.

nodemon watches files and restarts on every save, which is what you want locally.

Create an express.Router per resource, such as users or orders, and mount them on paths like /api/users.

Register a four-argument middleware last: err, req, res, next.

helmet sets security-related HTTP headers such as Content-Security-Policy defaults, X-Content-Type-Options, and frame guards.

Build the React app, then use express.static to serve the dist or build folder.

Use a schema library such as Zod, Joi, or express-validator before business logic runs.