freeCodeCamp vs Debugging

Are you just starting your coding journey, or do you just want to know more about coding? Then freeCodeCamp is the place for you! Our Mobile app includes our Challenges, Tutorials, and Podcast Services, to get your coding-knowledge up to speed! If you are using the app for quite some time you can consider adding your own contribution to the app by visiting our open-source platform on GitHub. You can find our repository on: https://github.com/freecodecamp/mobile, we love to hear from you!

Debugging: Inside the Machine is a free debugging-practice arcade platformer for students preparing for AP Computer Science Principles or AP Computer Science A. You're inside a corrupted machine — find the USB Key, fix the glitches, and escape the firewall before the system collapses. CSP and CSA modes ship in the same app. Tap once to switch. — EASY · MED · HARD — Each difficulty is a different level, with its own glitch tilemap and its own question bank. CSP topics: Selection, Iteration, Functions & Lists. CSA topics: Variables · Strings, Iteration · Loops, Arrays · Recursion. Two bonus levels (K-Pop Demon Hunters, Minecraft) unlock when you've cleared all three difficulties. — CODE LENS — Glitches scatter across each level as collectible bugs. When you're in range, the CODE LENS button pulses on screen. Tap it and a real multiple-choice debugging question appears: read the broken code, pick the actual bug from four explanations, and the glitch repairs. Wrong answer? Stability drops 10 percent. Right answer? Stability recovers 5 percent and the level inches closer to stable. — Real questions, not filler — Every question is hand-written and scoped to AP exam topics. No random AI hallucinations, no off-curriculum trivia. The pseudocode reference card (CSP) and Java Quick Reference (CSA) are one tap away during any question. — Built for phones and tablets — Touch controls only. Bottom-left D-pad to move, big JUMP button on the right, hold for higher jump. Question screens use full-size answer buttons. Designed for landscape iPhone and iPad. — Offline, no account, no tracking — Everything ships in the app. The game makes zero network calls, collects zero analytics, and requires no sign-in. — More from CS++ — A "More from CS++" button connects you to the rest of the CS++ family: the AP CSP and AP CSA full-curriculum apps, the CS++ Java IDE for on-device Java practice, and the free csplusplus.com web resources (curriculum, vocab trainer, practice exams). For: AP CSP and AP CSA students, CS teachers building exam prep sessions, anyone who likes finding bugs.