Note
While this was originally written for Magento developers, the framework applies to interviewing any e-commerce or PHP developer. The principles of evaluating technical depth, development practices, and infrastructure knowledge are universal.
The challenge
It's very difficult to determine the knowledge and expertise of a candidate until they're actually working on a project. A well-structured interview can help bridge this gap by exploring not just what candidates know, but how deeply they understand it.
The key is to use questions as starting points for deeper discussion, not as a checklist for yes/no answers. A candidate who can explain their reasoning and discuss trade-offs demonstrates genuine expertise.
Technical knowledge
Platform experience
- How long have you worked with this platform/framework?
- What's the most challenging technical problem you've solved?
- Are you certified? If not, why not?
- How do you stay current with platform updates and security patches?
Architecture understanding
- Explain the EAV (Entity-Attribute-Value) model and its trade-offs
- How does the tax calculation system work?
- Describe the payment processing flow
- What performance optimisation techniques have you used?
- How do you approach caching strategy?
Development practices
Debugging and quality
- What debugging tools do you use? (xdebug, profilers, etc.)
- How do you approach logging in production vs development?
- What's your experience with unit testing frameworks?
- Do you use static analysis tools?
Version control and CI/CD
- Describe your Git workflow (branching strategy, code review process)
- How do you handle database migrations?
- What's your experience with continuous integration?
- How do you manage deployments across environments?
Infrastructure knowledge
Not only application knowledge is necessary. A well-rounded developer understands the infrastructure their code runs on:
- Apache/Nginx configuration and optimisation
- MySQL query optimisation and indexing
- Cron job management and monitoring
- Basic Linux administration
- Understanding of caching layers (Varnish, Redis, Memcached)
Project management
- What issue tracking systems have you used?
- How do you estimate development time?
- Describe your approach to code reviews
- How do you handle scope changes mid-project?
The right approach
Remember: these questions are meant to spark discussion, not test memorisation. Look for candidates who:
- Explain their reasoning: Why they chose a particular approach
- Acknowledge limitations: What they don't know and how they'd find out
- Discuss trade-offs: No solution is perfect; good developers understand compromises
- Share real experiences: Specific examples from actual projects
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