Tell me about a PHP project you have worked on. What was your role and what was challenging?

Note: PHP interviews often start here because the ecosystem spans everything from a 2005 procedural codebase to modern Laravel. The interviewer is placing you on that spectrum.

Cover:

• What it was and its scale. Traffic, database size, number of developers. Say whether it was greenfield or an existing system, because they are entirely different skills.
• The stack, honestly. PHP version, framework or none, database, and how it was deployed. If it was legacy procedural PHP, say so — having survived that is a credential, not an embarrassment.
• The hard part. Good candidates: an upgrade from PHP 5 to 7 or 8, N+1 queries under load, a session or caching problem that only appeared on multiple servers, or introducing tests to a codebase that had none.
• The outcome, with a number. Response time, error rate, or deploy frequency before and after.