Loop Support
Need help? Get in touch through our contact page. We usually reply within two days.
Common questions
Where do I start? Open the Dashboard. The card at the top shows the next lesson on your path; tap Start (or Continue) to open it. The four tracks are Data Structures & Algorithms, System Design, the Interview Playbook, and AI Engineering with Claude. You can study them in any order.
How do the animations work? Every animation has the same controls under it: play and pause, step forward, step back, restart, and a bar you can drag to jump to any step. The line above the controls explains what's happening at the current step. The speed button (1x) cycles through slower and faster playback.
How do I mark progress? At the end of a lesson, tap Mark complete. On a problem, tap Attempted, Solved or Review; tap the same button again to clear it. A practice lesson completes itself once every problem in it is solved. A checkpoint (a short quiz) counts as passed when you get at least 70% of the answers right.
What is the streak? The number of days in a row you've completed at least one thing: a lesson, a solved problem or a checkpoint. Today counts as soon as you finish something. Days follow UTC (Coordinated Universal Time), so on the US West Coast a new day starts at 5 pm (4 pm in winter).
Do I need an account? No. Everything works without one; your progress is saved in this browser. An account only keeps your progress in step across devices. Use Sign in to sync in the sidebar.
My progress is missing on another device. Sign in with the same email on both devices. Progress made before you signed in on a device is merged into your account the first time you sign in there.
Where's my scratchpad code? Scratchpad notes are saved only in the browser where you typed them. They don't sync.
How do I start over? Progress → Reset all progress. If you're signed in, this clears your progress on every device. There's no undo.
How do I delete my account? Ask through our contact page, giving the address you signed up with, and we'll delete the account and its progress.
Privacy
See the privacy policy.