How to understand that the backend is working poorly, where is it slowing down? How to debug a 500 error in production?

To understand that the backend is performing poorly and where exactly the bottlenecks occur, you need to conduct performance analysis and log review:

• Monitoring and metrics: Use monitoring tools (e.g., Prometheus, Grafana, New Relic) to track response times, server load, CPU and memory usage.
• Logging: Analyze server logs to identify slow requests, errors, and exceptions.
• Request tracing: Implement distributed tracing (e.g., Jaeger, Zipkin) to understand at which stage of the request delays occur.

For debugging a 500 error in production:

1. Check error logs: Usually, a 500 error is accompanied by a stack trace in the logs.
2. Identify the request: Determine which request caused the error and with what parameters.
3. Check external dependencies: Sometimes, the error is related to the database, third-party services, or resources.
4. Reproduce the error: If possible, reproduce the error in a testing environment.
5. Add additional logging: Temporarily increase the logging level for complex cases.

It is important to have a configured alerting and monitoring system to quickly respond to such errors.