What methods can be used to ensure that your application is functioning correctly?

Several approaches are used to ensure that the application functions correctly:

1. Testing — writing and running unit, integration, and functional tests to verify logic and component interactions.
2. Monitoring — collecting metrics (load, response time, errors) using tools (Prometheus, Grafana, Datadog).
3. Logging — analyzing logs to identify errors and anomalies.
4. Health checks — special endpoints or scripts that verify the availability and status of services.
5. Load testing — simulating real load to assess stability.

For example, you can set up an endpoint /health in the application that returns the status "OK" during normal operation, and configure the monitoring system to make regular requests to it.