18Software Engineering · Interview Prep · Free
PHP Developer interview questions — and how to answer them.
These are the questions PHP Developer candidates are most likely to face, from openers to the hard ones — each with a note on what a strong answer covers. Want more, tuned to your level? Use the free generator below.
What interviewers look for in a PHP Developer
- Concrete examples of systems you've built, with the trade-offs you weighed
- How you debug — the process, not just the fix
- Collaboration signals: code review, disagreements, mentoring
Likely PHP Developer interview questions
1. Tell us about your experience with PHP. What versions have you worked with and what projects have you built?
Demonstrates practical experience, familiarity with PHP evolution, and portfolio of completed work
2. What PHP frameworks have you used, and why do you prefer one over another?
Shows framework knowledge (Laravel, Symfony, etc.), understanding of tradeoffs, and thoughtful technology choices
3. Describe your experience with relational databases. How do you optimize database queries?
Covers SQL knowledge, indexing strategies, query optimization, and understanding of N+1 problems
4. Walk us through how you approach debugging a production issue in a PHP application.
Reveals problem-solving methodology, logging practices, use of tools, and production environment understanding
5. How do you handle authentication and authorization in your PHP applications?
Demonstrates security awareness, knowledge of sessions/tokens, password hashing, and role-based access control
6. Explain your experience with RESTful APIs. How do you design and test them?
Shows API design principles, HTTP methods, status codes, testing frameworks, and documentation practices
7. What testing practices do you follow? Describe your experience with unit tests, integration tests, and test frameworks like PHPUnit.
Indicates commitment to code quality, TDD familiarity, understanding of test coverage, and frameworks used
8. How do you manage dependencies in PHP projects? What's your experience with Composer?
Demonstrates package management knowledge, version constraints understanding, and autoloading concepts
9. Tell us about your experience with design patterns in PHP. Give an example of when you applied one.
Shows knowledge of MVC, singleton, factory, repository patterns, and ability to apply them appropriately
10. Describe how you would approach refactoring legacy PHP code. What metrics or tools do you use?
Reveals code quality focus, knowledge of technical debt, static analysis tools, and incremental improvement strategies
11. Walk us through implementing caching in a PHP application. When would you use Redis vs Memcached?
Demonstrates performance optimization knowledge, understanding of cache invalidation, and tool-specific tradeoffs
12. How would you design a scalable PHP architecture for a high-traffic application? What considerations matter most?
Shows systems thinking, load balancing awareness, database scalability, caching layers, asynchronous processing, and monitoring
Want to practice answering live with scored feedback? Try the Mock Interview Coach. Applying too? See a PHP Developer cover letter example.
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