What a junior front-end developer should know

The mandatory minimum

Markup and styling. Not superficially: semantics, the box model, modern layout methods, responsiveness on phones. Building a page from a design is a base skill that's checked almost every time.

JavaScript. Data types, functions, working with arrays and objects, changing the page from code, handling events, asynchrony and requests to a server.

Asynchrony is where people most often flounder. Learn it properly.

One framework. Usually React, sometimes others. Components, state, passing data down, rendering lists, simple routing.

One. Not three superficially.

Tooling. Version control, package management, an idea of how the project is built.

Browser developer tools. Being able to see which request went out, why an element looks wrong, where the error is.

What can wait

• Static typing — useful, not always required at entry.
• Interface testing.
• State management beyond what's built in.
• Loading optimisation.
• Server-side rendering.

These appear in postings, but usually as nice-to-haves.

What to show in a project

One finished interface where the following is visible:

• working with server data, including loading and error states;
• forms with input validation;
• responsiveness — it opens on a phone;
• a tidy structure where it's clear what lives where.

A list screen, an item page and an add form is already a sufficient set, if done neatly.

Where interviews go wrong

Asynchrony. "Why did this run in that order" is the classic question that separates understanding from memorisation.

How a page works. What happens between typing an address and seeing pixels. Asked often, answered poorly.

Layout by feel. Someone can assemble an interface from ready components but can't build a simple layout by hand.

Not knowing the browser tools. A candidate who can't inspect network requests looks like someone who has never debugged anything.

Testing yourself

Build a page from scratch without component libraries: layout, responsiveness, data loading, error handling. If it works, the minimum is covered.

And show it to someone who writes front-end. A review through other eyes finds what you can't see — and those are exactly the places interviews pick at.