65+ K6 Interview Questions and Answers [Performance Testing – 2025]

Core K6 Concepts

1. What is the primary purpose of K6 in DevOps?

K6 is a modern performance testing tool used to simulate load, stress, and spike tests for APIs and web applications. It integrates with cloud networking practices, Prometheus for metrics, and GitLab for CI/CD pipelines, ensuring robust performance validation.

2. Why is K6 preferred for performance testing?

• JavaScript-based scripting for flexibility.
• Scalable load generation.
• Integration with Prometheus metrics.
• Support for GitLab CI/CD.
• CLI for automated testing.
• Real-time result analysis.
• Compliance with testing standards.

3. When should K6 be used in a pipeline?

• Validating API performance.
• During CI/CD deployments.
• Testing Kubernetes workloads.
• Integrating observability tools.
• Automating performance workflows.
• Troubleshooting latency issues.
• Validating with team reviews.

4. Where does K6 execute performance tests?

K6 executes tests locally, in CI/CD pipelines, or cloud environments, integrating with Prometheus for metrics, Grafana for visualization, and GitLab for test automation to ensure accurate performance insights.

5. Who manages K6 test deployments?

DevOps engineers configure K6 tests, SREs optimize performance, QA specialists validate results, and auditors review compliance. They coordinate via Jira, with team leads overseeing deployments and executives monitoring metrics.

Regular audits ensure test reliability.

6. Which K6 components are critical for testing?

• JavaScript scripts for test logic.
• CLI for test execution.
• Prometheus for performance metrics.
• Grafana for result visualization.
• GitLab for test versioning.
• APIs for automation tasks.
• Logs for compliance tracking.

7. How does K6 simulate real-world load?

K6 simulates real-world load using JavaScript scripts to define virtual users (VUs) and scenarios, integrating with Prometheus for metrics and GitLab for CI/CD to validate application performance under stress.

8. What if K6 tests fail to run correctly?

• Verify script syntax errors.
• Check CLI configurations.
• Inspect network connectivity.
• Integrate Prometheus for diagnostics.
• Test scripts in staging setups.
• Escalate via Jira for resolution.
• Monitor trends with analytics.

9. Why do K6 tests produce inconsistent results?

• Incorrect virtual user configurations.
• Network latency fluctuations.
• API endpoint instability.
• Misconfigured Prometheus metrics.
• Untracked analytics for failures.
• Inconsistent test environments.
• Lack of team validation.

10. When should K6 tests be optimized?

• Scaling large test scenarios.
• During CI/CD pipeline updates.
• Integrating observability tools.
• Validating Kubernetes performance.
• Automating test workflows.
• Troubleshooting result issues.
• Validating with team reviews.

11. Where does K6 store test configurations?

K6 stores test configurations in JavaScript files, managed in GitLab repositories, integrating with GitLab workflows, Prometheus for metrics, and CI/CD pipelines for automation.

12. Who validates K6 test configurations?

QA engineers validate K6 scripts, SREs review performance, DevOps specialists manage CI/CD, and auditors ensure compliance. They coordinate via Jira, with team leads overseeing validations and executives monitoring metrics.

Scheduled audits maintain configuration accuracy.

13. Which K6 features optimize performance testing?

• Virtual users for load simulation.
• Scenarios for test customization.
• Prometheus for performance metrics.
• Grafana for result visualization.
• GitLab for test versioning.
• CLI for automated execution.
• Logs for compliance tracking.

K6 Scripting and Test Design

14. How does K6 use JavaScript for test scripts?

K6 uses JavaScript to define test scripts, specifying virtual users, scenarios, and HTTP requests. It integrates with Prometheus for metrics, Grafana for visualization, and GitLab for versioning to create robust performance tests.

15. Why do K6 scripts fail to execute?

• Incorrect JavaScript syntax.
• Misconfigured virtual users.
• API endpoint connectivity issues.
• Compliance restrictions on scripts.
• Network latency affecting tests.
• Untracked analytics for failures.
• Inconsistent script reviews.

16. When should K6 scripts be refactored?

• Optimizing complex test scenarios.
• During CI/CD pipeline updates.
• Integrating observability tools.
• Validating Kubernetes performance.
• Automating test workflows.
• Troubleshooting script issues.
• Validating with team reviews.

17. Where does K6 execute test scripts?

K6 executes test scripts in local, cloud, or CI/CD environments, integrating with fault-tolerant designs, Prometheus for metrics, and GitLab for versioning.

18. Who develops K6 test scripts?

QA engineers write K6 scripts, SREs optimize performance, DevOps specialists manage CI/CD, and auditors review compliance. They coordinate via Jira, with team leads overseeing development and executives monitoring metrics.

Regular audits ensure script reliability.

19. Which tools complement K6 scripting?

• JavaScript for test logic.
• Prometheus for performance metrics.
• Grafana for result visualization.
• GitLab for script versioning.
• CLI for automated execution.
• APIs for test automation.
• Logs for compliance tracking.

20. How does K6 handle complex test scenarios?

K6 handles complex test scenarios using JavaScript scenarios to define load patterns, integrating with Prometheus for metrics, Grafana for visualization, and GitLab for CI/CD to manage intricate performance tests.

21. What if K6 scenarios cause test failures?

• Verify scenario configurations.
• Check JavaScript syntax errors.
• Inspect network connectivity.
• Integrate Prometheus for diagnostics.
• Test scenarios in staging setups.
• Escalate via Jira for resolution.
• Monitor trends with analytics.

22. Why do K6 scenarios impact test performance?

• Complex virtual user logic.
• High load generation overhead.
• API endpoint instability.
• Compliance restrictions on tests.
• Network latency affecting results.
• Untracked analytics for delays.
• Inconsistent scenario reviews.

23. When should K6 scenarios be optimized?

• Scaling large test workloads.
• During CI/CD pipeline updates.
• Integrating observability tools.
• Validating Kubernetes performance.
• Automating scenario workflows.
• Troubleshooting performance issues.
• Validating with team reviews.

24. Where does K6 store test scenario files?

K6 stores test scenario files in GitLab repositories, integrating with Prometheus for metrics and CI/CD pipelines for automation to ensure versioned and reliable test management.

25. Who refactors K6 test scenarios?

QA engineers refactor scenarios, SREs optimize performance, DevOps specialists manage CI/CD, and auditors review compliance. They coordinate via Jira, with team leads overseeing refactoring and executives monitoring metrics.

Periodic audits ensure scenario efficiency.

26. Which K6 features support scenario optimization?

• Scenarios for load customization.
• JavaScript for modular scripts.
• Prometheus for performance metrics.
• Grafana for result visualization.
• GitLab for scenario versioning.
• CLI for automated execution.
• Logs for compliance tracking.

Load and Stress Testing

27. How does K6 perform load testing?

K6 performs load testing by simulating virtual users with JavaScript scripts, generating HTTP requests to test API performance. It integrates with network protocols, Prometheus for metrics, and GitLab for CI/CD.

28. Why do K6 load tests fail?

• Incorrect virtual user settings.
• API endpoint overload.
• Network latency issues.
• Misconfigured Prometheus metrics.
• Untracked analytics for failures.
• Inconsistent test environments.
• Lack of team validation.

29. When should K6 load tests be executed?

• Validating API scalability.
• During CI/CD pipeline runs.
• Testing Kubernetes workloads.
• Integrating observability tools.
• Automating test workflows.
• Troubleshooting latency issues.
• Validating with team reviews.

30. Where does K6 run load tests?

K6 runs load tests in local, cloud, or CI/CD environments, integrating with Prometheus for metrics, Grafana for visualization, and GitLab for automation to ensure accurate performance results.

31. Who configures K6 load tests?

QA engineers configure load tests, SREs optimize performance, DevOps specialists manage CI/CD, and auditors review compliance. They coordinate via Jira, with team leads overseeing configurations and executives monitoring metrics.

Regular audits ensure test reliability.

32. Which K6 features support load testing?

• Virtual users for load simulation.
• Scenarios for test customization.
• Prometheus for performance metrics.
• Grafana for result visualization.
• GitLab for test versioning.
• CLI for automated execution.
• Logs for compliance tracking.

33. How does K6 perform stress testing?

K6 performs stress testing by increasing virtual users to identify system breaking points, integrating with scalable network designs, Prometheus for metrics, and GitLab for CI/CD.

34. What if K6 stress tests cause system crashes?

• Verify virtual user configurations.
• Check API endpoint stability.
• Inspect network connectivity.
• Integrate Prometheus for diagnostics.
• Test in staging environments.
• Escalate via Jira for resolution.
• Monitor trends with analytics.

35. Why do K6 stress tests fail?

• Overloaded API endpoints.
• Incorrect test configurations.
• Kubernetes resource constraints.
• Compliance restrictions on tests.
• Network latency affecting results.
• Untracked analytics for failures.
• Inconsistent test reviews.

36. When should K6 stress tests be optimized?

• Testing system breaking points.
• During CI/CD pipeline updates.
• Integrating observability tools.
• Validating Kubernetes performance.
• Automating test workflows.
• Troubleshooting crash issues.
• Validating with team reviews.

37. Where does K6 execute stress tests?

K6 executes stress tests in cloud or CI/CD environments, integrating with Prometheus for metrics, Grafana for visualization, and GitLab for automation to identify system limits.

38. Who optimizes K6 stress tests?

SREs optimize test configurations, QA engineers validate scripts, DevOps specialists manage CI/CD, and auditors review compliance. They coordinate via Jira, with team leads overseeing optimizations and executives monitoring metrics.

Periodic audits ensure test efficiency.

39. Which tools enhance K6 stress testing?

• Scenarios for stress customization.
• Prometheus for performance metrics.
• Grafana for result visualization.
• GitLab for test versioning.
• CLI for automated execution.
• Kubernetes for workload testing.
• Logs for compliance tracking.

Observability and Monitoring

40. How does K6 enable observability in testing?

K6 enables observability by exporting test metrics to Prometheus, visualizing results in Grafana, and integrating with Prometheus monitoring and GitLab for CI/CD to ensure accurate performance insights.

41. Why does K6 observability data lack accuracy?

• Misconfigured Prometheus scrape jobs.
• Incomplete test metrics.
• Network latency affecting data.
• Compliance restrictions on telemetry.
• Kubernetes pod mismatches.
• Untracked analytics for inaccuracies.
• Inconsistent configuration reviews.

42. When should K6 observability be configured?

• Monitoring test performance.
• During CI/CD pipeline runs.
• Validating Kubernetes workloads.
• Integrating Prometheus metrics.
• Automating telemetry workflows.
• Troubleshooting data issues.
• Validating with team reviews.

43. Where does K6 collect observability data?

K6 collects observability data from test metrics, integrating with Prometheus for collection, Grafana for visualization, and GitLab for versioning to ensure reliable performance monitoring.

44. Who configures K6 observability tools?

SREs configure Prometheus and Grafana, QA engineers collect metrics, DevOps specialists manage CI/CD, and auditors review compliance. They coordinate via Jira, with team leads overseeing setups and executives monitoring metrics.

Regular audits ensure observability accuracy.

45. Which K6 features support observability?

• Metrics export for Prometheus.
• Grafana for visualization dashboards.
• Kubernetes for workload telemetry.
• GitLab for test versioning.
• CLI for automated telemetry tasks.
• APIs for observability integration.
• Logs for compliance tracking.

46. How does K6 integrate with Prometheus?

K6 integrates with Prometheus by exporting test metrics via HTTP endpoints, enabling scrape jobs for monitoring. It supports Grafana for visualization, GitLab for CI/CD, and staging for validation.

47. What if K6 observability data is incomplete?

• Verify Prometheus scrape configurations.
• Check test metric exports.
• Inspect network connectivity.
• Integrate Prometheus for diagnostics.
• Test telemetry in staging setups.
• Escalate via Jira for resolution.
• Monitor trends with analytics.

48. Why does K6 telemetry collection fail?

• Incomplete Prometheus setups.
• Test metric misconfigurations.
• Kubernetes pod mismatches.
• Compliance restrictions on telemetry.
• Network latency affecting data.
• Untracked analytics for failures.
• Inconsistent configuration reviews.

49. When should K6 telemetry be optimized?

• Tracking complex test metrics.
• During CI/CD pipeline runs.
• Validating Kubernetes performance.
• Integrating Prometheus metrics.
• Automating telemetry workflows.
• Troubleshooting data issues.
• Validating with team reviews.

50. Where does K6 send telemetry data?

K6 sends telemetry data to Prometheus for metrics and Grafana for visualization, integrating with Grafana visualization, Kubernetes for telemetry, and GitLab for versioning.

51. Who configures K6 telemetry tools?

SREs configure Prometheus and Grafana, QA engineers collect telemetry, DevOps specialists manage CI/CD, and auditors review compliance. They coordinate via Jira, with team leads overseeing setups and executives monitoring metrics.

Periodic audits ensure telemetry accuracy.

52. Which integrations enhance K6 observability?

• Prometheus for metric collection.
• Grafana for visualization dashboards.
• Kubernetes for workload telemetry.
• GitLab for test versioning.
• CLI for automated telemetry tasks.
• APIs for observability integration.
• Logs for compliance tracking.

CI/CD Integration

53. How does K6 integrate with CI/CD pipelines?

K6 integrates with CI/CD pipelines by running tests in GitLab runners, automating performance validation. It uses Prometheus for metrics, Grafana for visualization, and GitLab for test versioning to streamline workflows.

54. Why do K6 CI/CD integrations fail?

• Misconfigured GitLab runners.
• Incorrect test versioning.
• Kubernetes resource constraints.
• Compliance restrictions on pipelines.
• Network latency in test runs.
• Untracked analytics for failures.
• Inconsistent configuration reviews.

55. When should K6 CI/CD workflows be optimized?

• Automating test deployments.
• During pipeline performance tuning.
• Validating Kubernetes workloads.
• Integrating Prometheus metrics.
• Streamlining CI/CD pipelines.
• Troubleshooting integration issues.
• Validating with team reviews.

56. Where does K6 manage CI/CD test configurations?

K6 manages CI/CD test configurations in GitLab repositories, integrating with Prometheus for metrics and Kubernetes for workload testing to ensure automated performance validation.

57. Who configures K6 CI/CD integrations?

DevOps engineers configure GitLab pipelines, SREs optimize test runs, QA specialists validate scripts, and auditors review compliance. They coordinate via Jira, with team leads overseeing integrations and executives monitoring metrics.

Regular audits maintain CI/CD reliability.

58. Which K6 features support CI/CD integration?

• CLI for pipeline execution.
• GitLab for test versioning.
• Prometheus for test metrics.
• Grafana for result visualization.
• APIs for automated test tasks.
• Kubernetes for workload testing.
• Logs for compliance tracking.

59. How does K6 automate test execution in CI/CD?

K6 automates test execution using CLI commands in GitLab pipelines, integrating with SRE practices, Prometheus for metrics, and Grafana for visualization to ensure seamless testing.

60. What if K6 test automation fails?

• Verify CI/CD pipeline configurations.
• Check test script syntax.
• Inspect Kubernetes connectivity.
• Integrate Prometheus for diagnostics.
• Test automation in staging setups.
• Escalate via Jira for resolution.
• Monitor trends with analytics.

61. Why do K6 test executions cause pipeline disruptions?

• Incorrect pipeline configurations.
• Test versioning conflicts.
• Kubernetes resource constraints.
• Compliance restrictions on tests.
• Network latency in test runs.
• Untracked analytics for failures.
• Inconsistent configuration reviews.

62. When should K6 test automation be optimized?

• Streamlining CI/CD pipelines.
• Validating Kubernetes performance.
• During compliance-driven audits.
• Integrating Prometheus metrics.
• Automating test workflows.
• Troubleshooting pipeline issues.
• Validating with team reviews.

63. Where does K6 apply automated test executions?

K6 applies automated test executions in GitLab CI/CD pipelines, integrating with Prometheus for metrics, Grafana for visualization, and Kubernetes for workload testing to ensure reliable automation.

64. Who manages K6 test automation?

DevOps engineers manage CI/CD pipelines, SREs optimize automation, QA specialists validate tests, and auditors review compliance. They coordinate via Jira, with team leads overseeing automation and executives monitoring metrics.

Regular audits maintain automation reliability.

65. Which tools support K6 test automation?

• GitLab for pipeline automation.
• Prometheus for test metrics.
• Grafana for visualization dashboards.
• CLI for automated execution.
• Kubernetes for workload testing.
• APIs for automated test tasks.
• Logs for compliance tracking.

Security and Compliance

66. How does K6 ensure secure test environments?

K6 ensures secure test environments by isolating test runs and integrating with Vault for secret management. It uses cloud security practices, Prometheus for metrics, and GitLab for versioning.

67. Why do K6 test environments face security issues?

• Insecure test data handling.
• Misconfigured Vault secrets.
• Kubernetes namespace conflicts.
• Compliance restrictions on tests.
• Network latency affecting security.
• Untracked analytics for breaches.
• Inconsistent security reviews.

68. When should K6 test security be audited?

• After test environment updates.
• During compliance-driven audits.
• Validating Kubernetes security.
• Integrating Prometheus metrics.
• Automating security workflows.
• Troubleshooting security issues.
• Validating with team reviews.

69. Where does K6 apply security configurations?

K6 applies security configurations in test environments, integrating with Vault for secrets, Prometheus for metrics, and GitLab for versioning to ensure secure performance testing.

70. Who configures K6 test security?

Security engineers configure Vault, SREs optimize test environments, DevOps specialists manage CI/CD, and auditors review compliance. They coordinate via Jira, with team leads overseeing configurations and executives monitoring metrics.

Regular audits maintain security reliability.