Mid-LevelPerformance & Load Testing
What is Gatling and when would you choose it over other tools?
- gatling
- tool comparison
- performance tool
Answer it first, then compare. Nothing here is saved or scored.
Model answer
Gatling is a Scala-based performance testing tool with a DSL for writing simulations. Strengths: detailed HTML reports out of the box, excellent for CI integration, handles very high load efficiently (non-blocking I/O), recorder for capturing scenarios. Choose over k6 when: team knows Scala/Java, need beautiful built-in reports, testing WebSocket-heavy applications. Choose over JMeter when: need code-based tests (version control friendly), better performance at scale (JMeter uses threads, Gatling uses actors). All three are viable, pick based on team skills and reporting needs.
What interviewers listen for
- Workload modellingYou design the load shape from product traffic, not from tool defaults.
- Percentile literacyYou read p50/p95/p99 separately and explain why each matters.
- Bottleneck triageYou correlate metrics across application, database, and infrastructure layers.
- Capacity instinctsYou can translate a soak test into a sizing or scaling recommendation.