The 100 mistakes working developers make most.
Check them off, then make them truly yours with reflection.
Key Features
Don't stop at knowing the mistakes. Make them truly yours through reflection.
From writing code to working with a team, the mistakes that keep happening in the real world, organized by category.
Answer the reflection questions prepared for every mistake and build real understanding, not just memorization.
See your progress by category and overall, and feel yourself growing.
Use the same data on iPhone, iPad, and Mac. It syncs automatically with CloudKit.
Bookmark the items you want to revisit and review them together later.
Thanks to Mac Catalyst, the iPhone app works on your Mac just the same. Study anywhere.
10 Categories
Sorted by the situations junior developers actually run into.
Pricing
Try the first 30 for free, then unlock all 100 with PRO.
Free
Free
Free forever
PRO Monthly
Monthly
Price shown in the App Store
PRO Lifetime
Lifetime
Pay once, yours forever
Multi-Platform
With iCloud sync powered by CloudKit, start on any device and pick up on another.
30 free, all 100 with PRO.
Become a developer who never makes the same mistake twice.