Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

When Nginx returns upstream connection refused in your error logs, it means Nginx tr...

You set a breakpoint in your React component, but when you run the app, the debugger never stops ...

When you try to load a multi-gigabyte file into memory with Python, you often hit a MemoryE...

Fix Cloudflare Origin Certificate Mismatch Errors
If you see 'Origin Certificate Mismatch' in Cloudflare or browser warnings, it usually me...

Fix Git Push Rejected Non-Fast-Forward After Pull
You run git pull, then git push, and get: ! [rejected] non-fast-f...

Fix VS Code Terminal Not Opening on Mac
You open VS Code, press Ctrl+` or click the Terminal panel, and nothing happens. The...