Curated Learning Tracks

Challenge Collections

Hand-picked playlists focused on specific bug patterns and languages. Each collection takes 15 to 30 minutes to complete.

Five beginner-friendly bugs with clear symptoms and satisfying fixes. The best place to start if you are new to debugging.

Mutable default arguments, list.sort() returning None, and mutating a list while iterating over it.

Accidental string concatenation, array sort ordering numbers alphabetically, and zero being falsely treated as missing.

Fencepost errors, inclusive vs exclusive slice bounds, and loops that step one position too far.

The asynchronous bugs that silently swallow data: un-awaited promises, forEach loops with async callbacks, and race conditions.

Simulate modern Code Comprehension rounds: classic coding questions written by an AI that pass the obvious test, but break on subtle edge cases.

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