Level 01
Junior
Explain everyday PHP behavior and solve introductory PHP and SQL tasks.
About 55 minutes
Interview focus
Core fundamentals
PHP backend mock interview
Find bugs in realistic PHP code, write PHP and SQL solutions, and practice the decisions behind reliable workers, data processing, and backend services.
Designed by interviewers. Adapted to your answers. Scored against prepared criteria.
Choose your level
Rounds take about 55–60 minutes. The focus shifts from clear fundamentals to deeper production trade-offs.
Level 01
Explain everyday PHP behavior and solve introductory PHP and SQL tasks.
About 55 minutes
Interview focus
Core fundamentals
Level 02
Work through caching, retries, file processing, and practical PHP and SQL.
About 60 minutes
Interview focus
Practical application
Level 03
Explore worker lifecycles, resource limits, and failure recovery through code discussions, PHP, and SQL.
About 60 minutes
Interview focus
Production depth
What the round covers
Your selected level shifts the emphasis from fundamentals toward deeper production trade-offs.
Calibrated
to your selected level
Role-specific
coverage grounded in backend work
Adaptive
follow-ups shaped by your answers
Types, arrays, sessions, and request and worker lifecycles.
Write and fix PHP code for data processing, caching, and failure recovery.
Boundaries, dependencies, responsibilities, and provider integrations.
Transactions, race conditions, indexing, query behavior, and ORM pitfalls.
Write PostgreSQL queries for filtering, aggregation, joins, and data analysis.
Worker design, retries, idempotency, acknowledgements, and failure handling.
Authorization, injection, XSS, CSRF, secrets, tokens, and safe uploads.
DeepRound vs. ChatGPT
| Included | DeepRound | ChatGPT |
|---|---|---|
| Expert-designed interview scenario | Included with DeepRound | Not included in a general ChatGPT chat |
| Complete 45–50 min interview scenario | Included with DeepRound | Not included in a general ChatGPT chat |
| Role-specific interview structure | Included with DeepRound | Not included in a general ChatGPT chat |
| Structured question-by-question interview flow | Included with DeepRound | Not included in a general ChatGPT chat |
| Purposeful follow-ups for each question | Included with DeepRound | Not included in a general ChatGPT chat |
| Predefined evaluation criteria | Included with DeepRound | Not included in a general ChatGPT chat |
| Consistent scoring across the whole interview | Included with DeepRound | Not included in a general ChatGPT chat |
A real PHP interview structure where every question, follow-up, and evaluation criterion is there for a reason.
Review a sample answer and see what earned points, what was missing, and what to improve.
Completed
Overall score
76/100
Competency breakdown
Strengths
Uses measured plans and checks row estimates after clarification.
Needs attention
Explain how inaccurate row estimates can lead to a poor join or scan choice.
A PostgreSQL query has become slow as the table grows. How would you use EXPLAIN ANALYZE to find the bottleneck and decide what to change?
Databases & data consistency
Your answer
I’d run it on representative data and use actual timings and row counts, not estimated costs, to find expensive scans or sorts. If a scan reads many rows to return a few, I’d consider an index on the filter columns, then compare execution time before and after.
You distinguish measured execution from estimated costs, use actual timings and row counts to locate expensive work, and check whether the change helped.
Your initial answer suggests an index without comparing estimated and actual row counts.
Your clarification adds the missing comparison and a check for outdated statistics. The remaining gap is explaining how inaccurate estimates can lead to a poor join or scan choice.
Clarifying question
You mentioned actual row counts, but not how they compare with the planner’s estimates. What would a large difference tell you, and what would you check before adding an index?
Your clarification
I’d compare estimated and actual rows at each node. If the estimate is 100 rows but the query returns 50,000, I’d check whether statistics are out of date. I’d refresh them with ANALYZE, rerun the plan, and compare the estimates and execution time.
The full practice loop
Answer discussion questions out loud or in text, and write your solutions to coding tasks in the editor.
A prepared follow-up or focused clarification tests the reasoning behind your first answer.
Use the competency breakdown and answer-level feedback to decide what to revisit next.
Practice explaining the decisions that matter in a real PHP backend interview.
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