Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

You're running a Python script that generates a large file—maybe a CSV with millions of rows ...

You try to merge two Git branches and get this error:

fatal: refusing to merge unre...

Fix Nginx Upstream Connection Refused in Proxy Pass
When Nginx returns a 502 Bad Gateway or logs upstream connection refused

Nginx Permission Denied After Restart: Fixes That Work
After restarting nginx, you might see errors like connect() to unix:/var/run/php-fpm.sock f...

Fix Cloudflare DNS Propagation Taking Too Long
You updated DNS records in Cloudflare but changes still aren't live hours later. This is frus...

Python Requests Timeout: Example Code and Fixes
When using the Python requests library, a missing or misconfigured timeout can cause...