Weekly streak and XP rankings across all active learners. See where you stand.

Resurface questions you got wrong on a smart schedule so weak spots actually stick.

Leave a comment, ask a question, or share your solution approach below each lesson.

The certificate page uses CSS features not supported in older Safari versions, causing layout shifts on some iPhones.

Run zuzu challenges directly in your editor. Same tests, same feedback — your local environment.

Choose when your push notification fires — morning, lunch, or evening — to match your routine.

Star any lesson to save it. Jump back without hunting through the sidebar.

On 3G connections the selected answer briefly deselects and reselects after the API call returns.

The code editor briefly shows a blank white panel before the theme loads. More noticeable in dark mode.

Some email providers flag the magic-link OTP as promotional. Investigating DKIM/SPF headers and sender reputation.

On small screens the virtual keyboard pushes the Run/Submit button out of view. The editor should scroll or the button should float above the keyboard.

Navigating between lessons resets the sidebar scroll to the top, forcing you to re-scroll to your current position in long tracks.

Module names longer than ~30 characters overflow and get cut off in the header breadcrumb on narrow screens.

Lessons completed just after midnight in certain timezones sometimes count toward the wrong day, breaking an active streak.

Highlight key moments and save personal notes mid-lesson. Review them any time from your dashboard.

Weekly digest showing your streak, XP earned, and what lesson comes next. Keeps you accountable between sessions.

One-click share your completion certificate to LinkedIn or Twitter with a preview card.

Milestones for streaks, XP thresholds, and track completions. Earn badges you can show off on your certificate.