Overview

Two pieces, one small bridge

Chrome extension

Reads the problem on a practice site when you open it there, and writes a project with starter code and tests into a folder you choose. It works on its own.

Desktop app

For macOS, Windows, and Linux. Keeps a local library of your problems, writes projects without the folder prompt, and opens them in your editor, terminal, or file manager in one click.

The app opens on Today, which answers what to practice today. If a practice session is running, Back to your session takes you to it on Practice; otherwise, if an attempt is in progress on a project Bitling can open, Continue reopens it in your editor. Due today counts the problems due for review before your local midnight and names the most overdue one. Up next (below) suggests what to do, and Recently practiced shows the three problems you most recently opened or attempted, where each stands and why, and, for the most recent of them with a finished attempt, how your latest finished attempt on it went: its outcome, how long it took, and when. A problem on a blind reattempt shows only that the run is under way, and isn't counted as due until you finish. When part of your practice can't be read, Today says so instead of saying nothing is due. Only one button is the main one: continuing comes first, then the top suggestion, then Plan a practice session. If Bitling can't check what's in progress, no button is the main one, and a suggested drill waits (as it does while a session runs) until Try again finds no session open. There are no streaks. It's read each time you open Today, and again after you start something from it; nothing is stored.

When you finish an attempt in the Library, pick how it went, then answer a few optional questions: how it felt, what slowed you down, whether you'd recognize the pattern, and whether you could solve it again. Choose Save and finish to keep your answers with the attempt, or Skip and finish to finish without them.

Once you've solved a problem, Try it blind in the Library makes a fresh project for it from the problem as you captured it, with the template of its newest project and just the starter code, in a new folder: blind-reattempts/<platform>/<problem>/attempt-<n> inside your project folder. It's offered when nothing is in progress on the problem. Your earlier project folders aren't changed. Until you finish the blind attempt, the Library's history for that problem and your AI coach's view of it show only the blind attempt. Your old folders are still on disk, so staying blind is up to you.

Each problem in the Library shows where it stands, with a line saying why: Fresh (not tried), Learning (not solved yet), Assisted (your latest solve needed a Level 3 hint or more, or you noted you needed help), Independent, Retained (solved on your own in a blind reattempt, or a week or more after an earlier solve), or Due for Review. It's worked out from your attempts, hints, reflections and test runs each time the Library loads, and it's hidden during a blind reattempt.

When a problem comes due is a spaced-repetition schedule worked out from all your attempts at it. Your first clean solve (marked solved, with no failing tests in its last run) brings it back in 2 days if it needed a Level 3 hint or more, you noted you needed help, or it had two or more of a Level 1–2 hint, feeling hard and taking over an hour; in 7 days if it was a blind reattempt or you noted it felt easy, with no hint past Level 0, not noted as hard, and an hour or less from start to finish; and in 4 days otherwise. Each solve after that sets a new gap from how long it had been since the last one (coming back later than it was due earns half the extra days). It grows most after a blind reattempt or one you noted felt easy (no hint past Level 0, not hard, an hour or less), and least after one that needed a Level 3 hint or help, or had two of a Level 1–2 hint, feeling hard and taking over an hour. The gap never goes past a year. An attempt that ends partway, or is marked solved while its last test run had failures, brings the problem due right away, and the next solve starts the schedule over. Abandoned and reviewed attempts don't count. Until it's due, the Library says when the next review is.

Insights shows where each topic (one of your problems' tags) stands, with the counts behind it. Each problem counts once, by where it stands: solved on your own (Independent or Retained), solved with help (Assisted), or to try again (not solved yet, or its latest try slipped); one that's due for review counts where it stood. A topic looks solid when at least two problems were solved on your own and they outnumber the rest of its finished problems plus any it couldn't read; it's still growing the other way round. If every problem in a solid topic could be read and its newest solve on your own (no Level 3 hint or more, not noted as needing help) was 30 or more days ago, it says so. A problem whose history can't be read is counted as that, never guessed, and when such problems could change the call, there's no call yet. During a blind reattempt, the problem counts only as under way, so Insights shows nothing of its earlier attempts until you finish. It's worked out each time you open the page; nothing is stored.

Practice plans a session from your library. Pick a mode (Quick Practice, Interview Simulation, Topic Drill, Weakness Review, or Daily Challenge) and it lays out the blocks: core problems (after an easy warm-up in a Topic Drill, when your library has one to spare), then a short reflection and recall. While a session runs, the current block shows the time left, then how far past the plan you are. Nothing moves on by itself, and Pause stops the clock. The clock keeps counting while the session runs, even if your computer sleeps, up to 4 hours on a block, so pause when you step away. Small timer on top opens a small window with the current block's clock that stays above your other windows.

Up next on Today suggests what to practice, each with a line saying why. Problems due for review before your local midnight come first, most overdue first, up to five: one you last solved on your own offers Try it blind (or Start attempt when Bitling can't make a blind copy of it: its newest project uses your own template, its saved statement can't be read, or your project folder isn't available), and one you solved with help, or whose latest try slipped, offers Start attempt. Then up to three topics: ones Insights calls still growing, then solid ones with no solve on your own in 30 or more days. Start practice session plans a 45-minute Topic Drill on that topic, starts it right away and opens it on Practice, so a topic is suggested only when one of its problems has a project and no attempt in progress. A due problem Bitling can't start an attempt on (no project, because its folder was forgotten, or a newest project whose template Bitling doesn't recognize) is counted but not suggested. A problem with an attempt in progress isn't suggested, and during a blind reattempt nothing of its earlier attempts is used. A problem whose history can't be read is never suggested, only counted. It's worked out each time you open Today; nothing is stored.

Bitling is early and isn't published yet. The extension's store listing and the desktop installers are still being prepared, so there are no download links here yet.

Guides

• Getting started

  Install the extension and the desktop app, then hatch your first project.

• Sites and templates

  Which practice sites and project templates Bitling supports.

• Refresh and your files

  Which files are Bitling's, which are yours, and what Refresh does.

• Privacy and security

  What stays on your computer, and what the extension and desktop app can and can't do.

• Connect an AI client

  Add Bitling's local MCP server to Claude Code, Codex, Cursor, or another MCP client.

• Troubleshooting

  When the extension can't find the desktop app, and other messages you might see.

Coming later

These parts of Bitling aren't built yet, so they don't have guides. Each one gets a page here when it ships:

• the local coach's practice context and hints for the AI tool you already use (you can already connect that tool to Bitling's local MCP server), and
• optional sync between devices.