Featured guide
Debug a failed deployment
Separate build, configuration, startup and routing failures so each test answers one useful question.
More practical guidance
Triage an API request failureReduce a failing request to method, URL, authentication, payload and response evidence without exposing secrets.Plan a safe database migrationMake schema change, data movement, application compatibility and rollback observable before production traffic depends on them.
Quick checklist
- Commit and environment recorded
- First relevant error saved
- Failing stage identified
- Runtime and config compared
- One change tested at a time
Common problems
Build succeeds but the service is unhealthy
Inspect the start command, bind address, assigned port, migrations and startup time before changing application logic.
It works locally only
Compare runtime versions, case-sensitive paths, ignored files, environment variables and network dependencies.
What to do next
After recovery, write the root cause, detection gap and one preventive check into the project runbook.