Kong FAQs Asked in DevOps Interviews [2025]

Kong Core Concepts

1. What is Kong’s role in a microservices architecture?

Kong serves as an API gateway, managing routing, authentication, and rate limiting for microservices. It proxies requests to upstream services, enforcing policies without altering backends. Kong integrates with cloud-native observability, enabling DevOps teams to monitor performance across multi-cloud setups using tools like Prometheus.

2. Why use Kong for API authentication?

Kong’s plugin system supports real-time authentication (OAuth, JWT, Basic Auth), securing APIs without modifying services. Its scalability ensures low-latency processing for high-traffic applications, integrating with CI/CD for seamless updates in cloud-native environments.

3. When is Kong ideal for a new microservices project?

Deploy Kong when microservices require centralized routing, security, or monitoring. It’s critical for dynamic scaling or hybrid cloud setups, integrating with CI/CD for automated API lifecycle management in DevOps workflows.

4. Where does Kong fit in a Kubernetes architecture?

• API Ingress Controller: Routes external traffic to services.
• Security Policy Enforcement: Applies authentication and limits.
• Traffic Management Layer: Balances and transforms requests.
• Observability Integration: Connects to monitoring tools.
• Plugin Extension Framework: Customizes API behaviors.
• Service Discovery: Integrates with Kubernetes DNS.

5. Who manages Kong in a DevOps team?

DevOps engineers, API specialists, and SREs manage Kong, configuring services, routes, and plugins. They collaborate with security teams to ensure compliance, aligning with SLAs in cloud-native DevOps workflows.

6. Which databases are supported by Kong?

• PostgreSQL: Reliable for structured configurations.
• Cassandra: Scalable for high-availability setups.
• DB-less Mode: YAML-based for lightweight deployments.
• Hybrid Mode: Combines DB with declarative configs.
• Redis Cache: Accelerates query performance.
• Enterprise SQL: Supports custom large-scale databases.

7. How does Kong manage API routing?

Kong routes APIs using services and routes, matching paths or hosts to upstreams. It supports regex patterns and priority ordering, ensuring flexible traffic management for microservices in cloud-native environments.

8. What is Kong’s plugin system?

Kong’s plugin system extends functionality with modules for authentication, logging, and transformation. It supports custom Lua plugins, aligning with CI/CD pipelines for automated deployments in cloud-native architectures.

• Plugin Hooks: Intercepts request/response cycles.
• Custom Plugins: Lua-based for tailored logic.
• Enterprise Plugins: Advanced security and analytics.
• Plugin Repository: Community-contributed modules.
• Global vs Scoped Plugins: Flexible configuration.
• Plugin Validation: Ensures runtime compatibility.

9. Why use Kong for securing public APIs?

Kong secures public APIs with plugins like OAuth and JWT, enforcing authentication without backend changes. It centralizes identity management, ensuring robust security for cloud-native microservices.

10. When should you apply Kong’s rate limiting?

Apply rate limiting to prevent API abuse, throttling requests by IP or token. It’s critical for public APIs under heavy traffic, integrating with DevOps for dynamic policy updates.

11. Where are Kong entities stored in production?

• Database Backend: PostgreSQL or Cassandra tables.
• YAML Declarative Files: DB-less mode configurations.
• Git Repositories: Version control for entities.
• Helm Chart Values: Kubernetes deployment configs.
• Terraform State Files: Infrastructure as code.
• CI/CD Pipeline Artifacts: Automated entity updates.

12. Who benefits from Kong’s plugin extensibility?

API developers and DevOps teams benefit, customizing gateways with plugins for authentication or logging. This reduces custom code, streamlining management in cloud-native environments.

13. Which deployment modes does Kong support?

• DB-less Mode: YAML for lightweight setups.
• Hybrid Mode: Combines DB with declarative configs.
• Full Database Mode: Scalable for enterprise use.
• Kubernetes Operator: Automates cluster management.
• Docker Compose: Simplifies local deployments.
• Helm Charts: Kubernetes-native installations.

14. How does Kong integrate with Kubernetes?

Use the Kong Ingress Controller to manage services and routes as Kubernetes CRDs. It automates API gateway scaling, integrating with DevOps automation for cloud-native deployments.

15. What is Kong’s Admin API used for?

The Admin API provides programmatic control over Kong entities (services, routes, plugins), enabling automation of configurations. It supports CI/CD, ensuring seamless updates in cloud-native environments.

16. Why use declarative configuration in Kong?

Declarative configuration with YAML ensures reproducible Kong setups, simplifying environment consistency. It supports GitOps, enabling automated deployments in cloud-native DevOps pipelines.

17. When should you enable Kong’s OAuth plugin?

Enable the OAuth plugin for third-party authentication in public APIs, validating tokens with identity providers. It’s ideal for secure access, integrating with DevOps for policy automation.

18. Where do you configure Kong plugins?

• Admin API Endpoints: Programmatic plugin attachments.
• YAML Declarative Files: DB-less mode definitions.
• Kubernetes CRDs: Managed via Ingress Controller.
• Git Repositories: Tracks plugin configurations.
• Terraform State Files: Infrastructure as code.
• CI/CD Pipeline Scripts: Automates plugin deployments.

19. Who configures Kong plugins?

API architects and DevOps engineers configure plugins, selecting modules for authentication and rate limiting. They ensure compatibility, aligning with security requirements in cloud-native systems.

20. Which plugins enhance Kong’s security?

• OAuth2 Plugin: Handles token validation.
• Rate Limiting Plugin: Throttles API requests.
• CORS Plugin: Manages cross-origin policies.
• IP Restriction Plugin: Blocks unauthorized IPs.
• Request Transformer: Modifies headers securely.
• Response Transformer: Sanitizes output data.

21. How do you test Kong plugin configurations?

Test plugins using Postman for API calls, validating behaviors in staging. Use CI/CD pipelines to automate tests, ensuring reliability in cloud-native API gateways.

22. What does Kong’s request transformer plugin do?

The request transformer plugin modifies incoming requests, adding headers or rewriting paths. It enables API versioning, aligning with cloud-native ecosystems for microservices.

23. Why use Kong’s logging plugins?

Logging plugins capture request data for observability, integrating with tools like ELK or Splunk. They enable audit trails, supporting compliance in cloud-native DevOps environments.

24. When should you use Kong’s serverless functions?

Use serverless functions for lightweight edge logic like authentication or caching. They’re ideal for low-latency tasks, integrating with CI/CD for automated deployments.

25. Where are Kong serverless functions deployed?

• Kong Admin API: Manages function configurations.
• Git Repositories: Tracks function code versions.
• Terraform Configuration Files: Defines as code.
• API Endpoint Calls: Programmatic deployments.
• CI/CD Pipeline Scripts: Automates function rollouts.
• Kubernetes Manifests: Integrates with clusters.

26. Who develops Kong serverless functions?

Developers create serverless functions for edge tasks, collaborating with DevOps for deployment. They ensure low-latency logic in cloud-native API gateways.

27. Which languages support Kong serverless functions?

• Lua Scripting Language: Native for Kong plugins.
• JavaScript Runtime: Supports web-based logic.
• Go Compiled Code: Efficient for complex tasks.
• WebAssembly Binaries: Cross-language execution.
• Rust for Performance: High-speed edge processing.
• Python Limited Support: For simple tasks.

28. How do you debug Kong plugin configurations?

Debug plugins using Kong’s logging and Admin API, simulating requests in staging with tools like curl. Validate behavior, monitor metrics, and update via CI/CD for reliability.

29. What happens if Kong plugins are misconfigured?

Misconfigured plugins cause routing errors or security gaps, impacting API performance. Review logs, test in staging, and update via Git to ensure reliability in cloud-native workflows.

30. Why implement Kong’s health checks?

Kong’s health checks monitor upstream services, removing unhealthy targets from load balancing. They ensure reliable API routing, supporting high-availability in cloud-native microservices.

31. When should you use Kong’s circuit breaker?

Use the circuit breaker to prevent cascading failures by halting requests to failing services. It’s essential for resilient microservices, integrating with DevOps for automated recovery.

32. Where are Kong health checks configured?

• Upstream Entity Settings: Defines active/passive checks.
• YAML Declarative Files: DB-less mode configurations.
• Admin API Endpoints: Programmatic health updates.
• Git Repositories: Tracks health check versions.
• Terraform State Files: Infrastructure as code.
• CI/CD Pipeline Scripts: Automates health deployments.

33. Who sets up Kong health checks?

SREs configure health checks, setting intervals and thresholds for upstream monitoring. They collaborate with developers to ensure service reliability in cloud-native environments.

34. Which health check types are available in Kong?

• Active Health Checks: Periodic HTTP probes.
• Passive Health Checks: Based on response codes.
• TCP Connection Checks: Verifies port availability.
• HTTPS Endpoint Probes: Tests secure connections.
• Custom Script Checks: Lua-based validations.
• Threshold-Based Failures: Counts consecutive errors.

35. How do you validate Kong health checks?

Validate health checks by simulating service failures in staging, monitoring upstream status. Use CI/CD to automate tests, ensuring reliable routing in cloud-native API gateways.

36. How does Kong integrate with a service mesh?

Kong integrates with service meshes like Istio as an ingress gateway, managing external traffic. It enforces policies, aligning with cloud-native architectures for microservices.

37. Why use Kong’s declarative specification?

Declarative specification with YAML ensures reproducible Kong configurations, enabling GitOps. It simplifies management across environments, supporting automated deployments in cloud-native DevOps.

38. When is Kong’s consumer management useful?

Use consumer management for role-based API access, assigning credentials to users. It’s ideal for multi-tenant APIs, integrating with identity providers in cloud-native systems.

39. Where are Kong consumers configured?

• Admin API Endpoints: Programmatic consumer creation.
• YAML Declarative Files: DB-less mode definitions.
• Kubernetes CRDs: Managed via Ingress Controller.
• Git Repositories: Tracks consumer configurations.
• Terraform State Files: Infrastructure as code.
• CI/CD Pipeline Scripts: Automates consumer deployments.

40. Who manages Kong consumers?

API administrators manage consumers, assigning roles and credentials. They collaborate with security teams to ensure compliant access in cloud-native environments.

41. Which credentials does Kong support?

• API Key Authentication: Simple token-based access.
• Basic Auth Credentials: Username/password validation.
• HMAC Signature Keys: Secure message signing.
• JWT Token Handling: Validates signed tokens.
• OAuth2 Client Credentials: Supports token exchange.
• Mutual TLS Certificates: Enables client authentication.

42. How do you test Kong consumer access?

Test consumer access using tools like Postman, validating credentials and roles. Simulate in staging, monitor logs, and update via CI/CD for reliable API security.

43. How does Kong handle API versioning?

Kong supports API versioning by routing based on headers or paths, enabling multiple versions. It simplifies migrations, aligning with secure environments for microservices.

44. Why use Kong’s transformation plugins?

Transformation plugins modify requests and responses, enabling API compatibility and data masking. They support legacy integrations, enhancing flexibility in cloud-native DevOps.

45. When should you enable Kong’s CORS plugin?

Enable the CORS plugin to allow cross-origin requests, configuring headers for frontend-backend communication. It’s essential for SPAs, integrating with DevOps for automated policy updates.

46. Where are Kong CORS configurations defined?

• Plugin Configuration Block: Sets allowed origins.
• YAML Declarative Files: DB-less mode definitions.
• Admin API Endpoints: Programmatic CORS updates.
• Git Repositories: Tracks CORS policy versions.
• Terraform State Files: Infrastructure as code.
• CI/CD Pipeline Scripts: Automates CORS deployments.

47. Who sets up Kong CORS policies?

Frontend developers configure CORS policies, setting allowed origins and methods. They collaborate with API teams to ensure secure cross-origin access in cloud-native applications.

48. Which CORS settings are critical for Kong?

• Allowed Origins List: Specifies permitted domains.
• Allowed Methods Array: Defines HTTP verbs.
• Allowed Headers Configuration: Customizes request headers.
• Credentials Support: Enables cookie transmission.
• Max Age Setting: Caches preflight responses.
• Exposed Headers: Controls response visibility.

49. How do you verify Kong CORS configurations?

Verify CORS using browser dev tools or curl with --header flags, validating preflight requests. Simulate in staging and update via CI/CD for reliable cross-origin access.

50. How does Kong support service discovery?

Kong integrates with service discovery tools like Consul or Kubernetes, dynamically updating upstreams. It ensures scalable API routing, supporting real-time DevOps in microservices.

51. Why implement Kong’s upstream health checks?

Upstream health checks monitor service availability, removing unhealthy targets from routing. They ensure reliable API delivery, integrating with DevOps for automated recovery.

52. When should you use Kong’s circuit breaker?

Use the circuit breaker to prevent cascading failures by halting requests to failing services. It’s essential for resilient microservices, supporting automated DevOps recovery.

53. Where are Kong health checks configured?

• Upstream Entity Settings: Defines active/passive checks.
• YAML Declarative Files: DB-less mode configurations.
• Admin API Endpoints: Programmatic health updates.
• Git Repositories: Tracks health check versions.
• Terraform State Files: Infrastructure as code.
• CI/CD Pipeline Scripts: Automates health deployments.

54. Who configures Kong health checks?

SREs configure health checks, setting intervals and thresholds for upstream monitoring. They collaborate with developers to ensure service reliability in cloud-native environments.

55. Which health check types does Kong support?

• Active Health Checks: Periodic HTTP probes.
• Passive Health Checks: Based on response codes.
• TCP Connection Checks: Verifies port availability.
• HTTPS Endpoint Probes: Tests secure connections.
• Custom Script Checks: Lua-based validations.
• Threshold-Based Failures: Counts consecutive errors.

56. How do you test Kong health checks?

Test health checks by simulating service failures in staging, monitoring upstream status. Use CI/CD to automate tests, ensuring reliable routing in cloud-native API gateways.

Kong Security and Authentication

57. Why use Kong’s JWT plugin for API security?

The JWT plugin validates signed tokens, ensuring secure API access without backend changes. It’s ideal for microservices, aligning with cloud-native workflows for identity management.

58. When should you enable Kong’s IP restriction plugin?

Enable the IP restriction plugin to block unauthorized IPs, protecting APIs from abuse. It’s critical for sensitive endpoints, integrating with DevOps for dynamic security updates.

59. Where are Kong security plugins configured?

• Admin API Endpoints: Programmatic security settings.
• YAML Declarative Files: DB-less mode definitions.
• Kubernetes CRDs: Managed via Ingress Controller.
• Git Repositories: Tracks security configurations.
• Terraform State Files: Infrastructure as code.
• CI/CD Pipeline Scripts: Automates security deployments.

60. Who manages Kong security plugins?

Security engineers manage plugins, configuring OAuth, JWT, or IP restrictions. They collaborate with DevOps to ensure compliance in cloud-native API gateway deployments.

61. Which security plugins are essential for Kong?

• OAuth2 Plugin: Manages token-based authentication.
• JWT Authentication Plugin: Validates signed tokens.
• IP Restriction Plugin: Blocks unauthorized IPs.
• Rate Limiting Plugin: Throttles request rates.
• Bot Detection Plugin: Identifies malicious bots.
• Request Validator Plugin: Ensures valid payloads.

62. How do you test Kong security plugins?

Test security plugins using penetration testing tools like Burp Suite, simulating attacks in staging. Validate with CI/CD pipelines to ensure robust protection without blocking legitimate traffic.

63. What happens if Kong security plugins are misconfigured?

Misconfigured plugins can block legitimate users or expose vulnerabilities, degrading API security. Review logs, test in staging, and update via Git for reliable configurations.

64. Why use Kong for rate limiting in high-traffic APIs?

Kong’s rate limiting prevents API overload by throttling requests based on IP or token. It ensures availability, integrating with secure DevOps for automated scaling.

65. When should you adjust rate limiting thresholds?

Adjust thresholds during traffic spikes or false positives to balance access and security. Test in staging and deploy via CI/CD for optimized API performance.

66. Where are Kong rate limiting policies stored?

• Plugin Configuration Block: Defines throttling rules.
• YAML Declarative Files: DB-less mode definitions.
• Admin API Endpoints: Programmatic policy updates.
• Git Repositories: Tracks policy versions.
• Terraform State Files: Infrastructure as code.
• CI/CD Pipeline Scripts: Automates policy deployments.

67. Who tunes Kong rate limiting policies?

API administrators tune rate limiting, adjusting thresholds for traffic patterns. They collaborate with DevOps to ensure performance and security in cloud-native environments.

68. Which metrics track Kong rate limiting performance?

• rate_limit_exceeded_total: Counts throttled requests.
• request_rate_per_ip: Tracks IP-based traffic.
• rate_limit_latency_seconds: Measures throttling delays.
• api_request_total: Monitors overall request volume.
• rate_limit_violations: Logs policy breaches.
• consumer_request_rate: Analyzes per-consumer traffic.

69. How do you debug Kong rate limiting issues?

Debug rate limiting by reviewing logs, checking threshold settings, and testing in staging. Update policies via Git and CI/CD to balance access and protection in APIs.

70. How does Kong secure microservices?

Kong secures microservices with plugins for authentication, rate limiting, and encryption, enforcing policies at the gateway. It supports scalable, secure communication in cloud-native environments.

Kong Performance and Monitoring

71. Why monitor Kong performance metrics?

Monitoring metrics like latency and error rates detects bottlenecks, ensuring API reliability. It integrates with observability tools, supporting proactive fixes in DevOps configurations.

72. When should you analyze Kong logs?

Analyze logs during performance degradation or security incidents to identify root causes. It ensures optimal API operation, aligning with CI/CD monitoring in DevOps workflows.

73. Where are Kong logs stored?

• Kong Log Plugins: Streams to external systems.
• ELK Stack Integration: Centralizes log analysis.
• Prometheus Metrics Endpoints: Exposes performance data.
• Grafana Dashboards: Visualizes real-time logs.
• Kubernetes Log Systems: Captures containerized logs.
• Cloud Logging Services: Stores for compliance.

74. Who monitors Kong performance?

SREs monitor performance, analyzing metrics and logs for anomalies. They collaborate with DevOps to optimize API gateways in cloud-native environments.

75. Which metrics are critical for Kong performance?

• api_request_latency_seconds: Measures response times.
• upstream_response_time: Tracks backend delays.
• error_rate_total: Logs failed requests.
• request_throughput: Monitors traffic volume.
• plugin_execution_time: Tracks plugin performance.
• health_check_status: Reports upstream health.

76. How do you optimize Kong performance?

Optimize performance by tuning plugin execution, enabling caching, and load-testing in staging. Monitor metrics and update via CI/CD for efficient cloud-native API gateways.

77. What is the impact of poor Kong performance?

Poor performance causes high latency or downtime, degrading user experience. Tune configurations, test in staging, and deploy via Git to ensure reliability in DevOps workflows.

78. Why use Kong’s Prometheus plugin?

The Prometheus plugin exposes metrics for monitoring, integrating with Grafana for visualization. It supports real-time performance tracking, enhancing observability in cloud-native DevOps.

79. When should you enable Kong’s monitoring plugins?

Enable monitoring plugins for production APIs to track latency, errors, and traffic. They ensure proactive issue detection, integrating with CI/CD for automated monitoring.

80. Where are Kong monitoring plugins configured?

• Admin API Endpoints: Programmatic plugin setup.
• YAML Declarative Files: DB-less mode definitions.
• Kubernetes CRDs: Managed via Ingress Controller.
• Git Repositories: Tracks monitoring configurations.
• Terraform State Files: Infrastructure as code.
• CI/CD Pipeline Scripts: Automates monitoring deployments.

81. Who configures Kong monitoring plugins?

DevOps engineers configure monitoring plugins, integrating with tools like Prometheus. They ensure observability, aligning with performance goals in cloud-native environments.

82. Which monitoring plugins does Kong support?

• Prometheus Plugin: Exposes metrics for scraping.
• StatsD Plugin: Sends metrics to StatsD servers.
• Datadog Plugin: Integrates with Datadog dashboards.
• HTTP Log Plugin: Streams logs to endpoints.
• Syslog Plugin: Sends logs to syslog servers.
• File Log Plugin: Writes logs to files.

83. How do you test Kong monitoring plugins?

Test monitoring plugins by simulating traffic and validating metric output in Prometheus or Grafana. Use CI/CD to automate tests, ensuring reliable observability in APIs.

84. How does Kong enhance observability?

Kong enhances observability by exporting metrics and logs, integrating with tools like ELK and Prometheus. It supports end-to-end monitoring in cloud-native microservices.

Kong Troubleshooting and Best Practices

85. Why use Kong’s logging for troubleshooting?

Logging captures request and error data, enabling rapid diagnosis of issues. It integrates with observability tools, supporting proactive troubleshooting in scalable DevOps environments.

86. When should you escalate Kong issues?

Escalate issues when logs show persistent latency, errors, or security breaches. Use incident management tools and CI/CD alerts for quick resolution in DevOps workflows.

87. Where are Kong logs analyzed?

• Kong Log Plugins: Streams to external systems.
• ELK Stack Integration: Centralizes log analysis.
• Prometheus Metrics Endpoints: Exposes performance data.
• Grafana Dashboards: Visualizes real-time logs.
• Kubernetes Log Systems: Captures containerized logs.
• Cloud Logging Services: Stores for compliance.

88. Who troubleshoots Kong issues?

SREs troubleshoot issues, analyzing logs and metrics for root causes. They collaborate with DevOps to update configurations via Git, ensuring reliable API gateways.

89. Which tools aid Kong troubleshooting?

• Kong Admin API: Queries configuration state.
• Prometheus and Grafana: Visualizes performance metrics.
• ELK Stack: Correlates logs for analysis.
• Postman for Testing: Simulates API requests.
• Kubernetes Logs: Captures containerized issues.
• Terraform Plan Outputs: Validates config changes.

90. How do you handle Kong database issues?

Handle database issues by checking connectivity, validating schema, and monitoring performance. Test in staging, update via Terraform, and deploy with CI/CD for reliable backend integration.

91. What are best practices for Kong configurations?

Automate configurations with Terraform, use declarative YAML, and test in staging. Version control with Git and deploy via CI/CD to ensure reliability in cloud-native systems.

92. Why use canary deployments with Kong?

Canary deployments test new configurations on partial traffic, minimizing risks. They ensure stable rollouts, aligning with cloud-native DevOps for API gateways.

93. When should you rollback Kong changes?

Rollback changes when metrics show degraded performance or security issues post-deployment. Use Git to revert configs and CI/CD to redeploy for stability.

94. Where are Kong rollback configurations stored?

• Git Repositories: Tracks previous versions.
• Terraform State Files: Stores infrastructure state.
• YAML Declarative Files: DB-less mode backups.
• Admin API Snapshots: Captures entity states.
• CI/CD Pipeline Artifacts: Maintains rollback scripts.
• Kubernetes Manifest Backups: Stores cluster configs.

95. Who performs Kong rollbacks?

DevOps engineers perform rollbacks, reverting configurations using Git and CI/CD. They collaborate with SREs to ensure minimal disruption in cloud-native environments.

96. Which metrics trigger Kong rollbacks?

• api_error_rate_spike: Detects error surges.
• request_latency_high: Flags performance degradation.
• security_violation_count: Tracks policy breaches.
• upstream_failure_rate: Monitors backend issues.
• plugin_error_total: Logs plugin failures.
• traffic_drop_anomaly: Identifies sudden drops.

97. How do you resolve Kong SSL/TLS issues?

Resolve SSL/TLS issues by verifying certificates, enabling HSTS, and checking cipher suites. Test in staging and update via CI/CD for secure connections in deployments.

98. What is the impact of misconfigured Kong services?

Misconfigured services cause routing failures, security risks, or performance issues, impacting user experience. Review configs, test in staging, and update via Git for reliability.

99. Why integrate Kong with observability tools?

Integrating Kong with tools like Prometheus and ELK provides end-to-end visibility, correlating metrics and logs. It supports proactive issue resolution in DevOps certification workflows.

100. When should you use Kong’s canary testing?

Use canary testing to validate new plugins or routes on partial traffic, reducing deployment risks. It ensures stable updates, aligning with CI/CD in cloud-native systems.

101. How does Kong ensure high-availability?

Kong ensures high-availability with clustered deployments, load balancing, and health checks. It supports uptime, integrating with Kubernetes for scalable cloud-native API gateways.

102. What are best practices for Kong in production?

Use declarative configs, automate with Terraform, and monitor with Prometheus. Test in staging, version control with Git, and deploy via CI/CD for reliable, secure APIs in real-time DevOps.