PHP Developer Interview Questions (What Juniors Actually Get Asked)

Junior PHP interviews are won on fundamentals and Laravel habits, not algorithm puzzles. And almost everyone preps for the wrong thing.

I've sat on both sides of that table. I've watched candidates who could invert a binary tree freeze when I asked how they'd stop a SQL injection. I've hired people who couldn't do either puzzle but could walk me through a request from route to database like they'd lived there.

The hiring manager at a PHP shop isn't wondering if you can pass a Google interview. They're wondering if you'll break production in month two. Every question below exists to answer that one fear.

If you're still earlier in the journey, start with how to become a PHP developer and come back when interviews are on the calendar.

What junior PHP interviews actually test

Three things, in this order.

Can you explain your own code? Not recite definitions. Explain a thing you built, out loud, to another human.

Do you have safe habits? Prepared statements, validation, escaping output. Nobody expects a junior to architect a system. Everybody expects you not to paste user input into a query.

Will you be honest when you don't know? Interviewers push until you hit your edge on purpose, and they grade what you do there.

Here's the reframe I give every student: a junior interview isn't an exam you pass. It's a preview of what you'll sound like on the team.

PHP fundamentals questions

Expect most of these in some form.

What's the difference between == and ===? Double equals compares values after type juggling, so 0 == "abc" has burned real codebases. Triple equals compares value and type, no conversion. Say you default to === and treat == as a code smell. Loose comparison bugs are the classic PHP foot-gun, and your answer shows whether you've been bitten or just read about it.

How do you prevent SQL injection? Prepared statements, full stop. With PDO you bind parameters, so user input is sent as data, never interpolated into the query string. Escaping-by-hand is not a strategy. This is the single most important junior question; a wrong answer can end the interview.

What is XSS and how do you prevent it? Cross-site scripting is when user-supplied content gets rendered as live HTML or JavaScript in someone else's browser. The fix is escaping output: htmlspecialchars() in raw PHP, or Blade's {{ }} which escapes for you. Juniors who understand output escaping, not just input cleaning, think about security correctly.

Sessions vs cookies? Cookies live in the browser, so the user can read and tamper with them. Sessions live on the server; the cookie only carries the session ID. Sensitive state goes in the session. This checks whether you know where data physically lives, which is the root of half of web security.

require vs include? require throws a fatal error if the file is missing; include warns and keeps going. If the file matters, require it.

Also be ready for: which array functions you actually reach for (array_map, array_filter, in_array), how try/catch works and when you'd throw your own exception, and what Composer does. For Composer, the working-level answer: it installs dependencies from composer.json and generates an autoloader, so classes load by namespace without a wall of require statements.

Laravel interview questions

If the job listing says Laravel, half your interview lives here. (If you're weighing frameworks at all, my honest rundown is in best PHP frameworks, but for jobs, Laravel is the market.)

What is a migration and why use one? Version control for your database schema, written as PHP. Every teammate and server runs the same schema changes in the same order, and you can roll back. "I edited the table in phpMyAdmin" is the answer of someone who's never worked on a team.

Explain Eloquent relationships and the N+1 problem. A User hasMany Post; a Post belongsTo User. The N+1 problem is looping over 100 posts and lazily loading each author, which fires 101 queries. Eager loading with Post::with('user') makes it two. This one separates people who've used Laravel from people who've watched Laravel.

What is middleware? Code that runs before or after a request hits your controller: auth checks, CORS, logging. Describe it as layers the request passes through; it shows you understand the request lifecycle.

How does validation work? Inline $request->validate() for quick cases, Form Request classes when rules get long or reused; failures redirect back with errors automatically. Bonus points for saying validation protects the database, not just the form.

Queues, and when do you use them? Anything slow the user shouldn't wait on: sending email, processing uploads, calling third-party APIs. Dispatch a job, return fast, let a worker handle it. It signals you think about user experience under load.

Also expect: route model binding (Laravel resolves /posts/{post} into a Post model or 404s for you), Blade views vs JSON API responses and when each fits, and why .env values are read through config() because config:cache in production freezes config and skips the env file.

Database and practical questions

What's an index and when does a query need one? An index lets the database find rows without scanning the whole table. Any column you regularly filter, join, or sort on is a candidate; WHERE email = ? on a million-row users table is the textbook case. The tradeoff is slower writes, and saying that out loud is what makes the answer senior-sounding.

Explain JOIN types conversationally. INNER JOIN gives rows that match in both tables. LEFT JOIN gives everything from the left table, with nulls where there's no match. That's 95% of daily work; don't panic about the exotic ones.

Also expect: how you'd debug a slow endpoint. The winning shape is a process: reproduce it, check the query log or Laravel Debugbar, look for N+1s or missing indexes, measure again after the fix.

Scenario questions

These are where offers get decided.

"Users report the app is slow every day around noon, where do you look?" Start with data, not code: server metrics and logs at that hour. Noon spikes usually mean traffic peaks or a scheduled job hogging the database, so I'd check the cron schedule, the slow query log, and whether a heavy report or email blast runs midday. The interviewer doesn't need the right culprit; they need to see you investigate instead of guess.

"A teammate pushed a migration that dropped a column in production. What now?" First, stop the bleeding: is data actually gone, and is there a backup? Restore from the most recent backup, communicate loudly and early, and don't spend one second blaming the teammate. Then fix the system: staging environment, review on migrations, backups tested. They're testing your temperament under fire more than your SQL.

Also floating around: "a feature works locally but not in production" (environment config and caching) and "how would you add a feature to a codebase you've never seen" (read the routes file, trace one request).

Questions YOU should ask them

Asking nothing reads as not caring. Ask:

• "What does code review look like here?" Tells you if you'll get mentorship or be alone.
• "What's the deploy process?" One-command deploys vs FTP-and-pray tells you everything about the codebase.
• "What would my first two weeks look like?" Companies that can answer have onboarding. Companies that can't, don't.
• "How do juniors here grow into mid-level?" Signals ambition, and helps when you negotiate later. Know your numbers from the PHP developer salary guide first.
• "Is the team remote, hybrid, or in-office day to day?" If you're hunting remote PHP developer jobs, you want the real answer, not the listing's.

How to prepare in the week before

Skip the puzzle grind. One deployed Laravel app you can walk through end-to-end beats fifty solved algorithm problems, because it turns every question above into a story you lived.

Rehearse explaining one feature out loud: route, to controller, to model, to view. Literally say it to a wall. The first time you narrate your own code should not be in the interview. If you don't have a project worth walking through yet, steal a shape from these PHP portfolio examples and ship a small one.

Then reread your own résumé, because everything on it is fair game. Our members run theirs through the CodingPhase résumé builder to get past ATS screening, and pull real openings from the job board so prep matches actual listings.

Honest part: you can't prep for everything. Every interviewer has a pet question, and some will ask something you've never touched. That's fine. "I haven't used that, but here's how I'd figure it out" has gotten more of my students hired than a bluffed answer ever has.

FAQ

Do PHP interviews include live coding? Sometimes, but for juniors it's usually small and practical: a FizzBuzz-level exercise, a bug hunt, or a take-home CRUD feature. Full whiteboard algorithm rounds are rare outside big tech.

How many interview rounds do junior PHP jobs have? Usually two or three: a screen, a technical conversation, and a culture or founder chat. Small agencies sometimes do it all in one call.

Do I need to know Laravel for a PHP interview? For most PHP jobs in 2026, yes at a working level. Plain-PHP-only shops exist, but Laravel is the default assumption in job listings.

What should I say when I don't know an answer? Say so, then reason out loud about how you'd find out. Interviewers grade the recovery, not the gap.

How long should I prepare for a PHP interview? If you've built and deployed real projects, one focused week reviewing the topics above is plenty. If you haven't built anything, no amount of question-memorizing will cover for it.

If you're staring down your first PHP interview, remember it's a conversation with a future teammate, not a trial. Walk in with one project you know cold and honest answers for the rest, and you're ahead of the room. And if you want the full roadmap with courses, projects, and people who've done this before you, that's what the PHP developer career path is for. I'm rooting for you.