Any timer can tell you that you averaged 19 seconds. Almost none can tell you which part of those 19 seconds is worth attacking next. CubeBloom exists for that second question.
CubeBloom splits a solve into its phases — cross, F2L, OLL, PLL on 3×3, and the equivalents on One-Handed, 2×2, 4×4 and Megaminx. It separates recognition from execution and shows you which phase is furthest above its typical share.
What to actually practise is the AI coach's answer, not a threshold's. It reads your phase splits, your consistency, your algorithm progress and every event you have touched, and picks from the drill library on that. The library itself stays open — every drill in the app is on one page, all of the time.
Three ways to get those phase times: record a solve on your camera, scrub through a video you already have, or connect a Bluetooth smart cube — the only one of the three that is exact rather than estimated.
Constraints the app is built around, not marketing lines. Each one made the app less impressive-looking and more honest.
An earlier version divided a timed solve across the typical share for each phase and stored it as if measured — so every “your F2L is slow” downstream was reading invented numbers. Now a timed solve records a total, and every phase view says the splits aren't there rather than guessing.
Camera and video analysis run entirely in your browser. Quick-record footage is discarded the moment it is analysed, and files you load are never uploaded. Only phase times — numbers — are ever sent anywhere, and only when you ask the coach a question.
csTimer's multi-phase marks come in more than one order, so the importer detects the format per record instead of betting on one. Marks that fail the arithmetic become a total-only solve. A wrong guess would put real numbers under the wrong labels — the exact failure this app avoids.
All 117 algorithms in the trainer are checked by a script that applies each one to a virtual cube and confirms it solves the case it claims to. It runs as npm run verify:algs, and every set is checked for completeness too.
In your browser, and nowhere else. No account, no sync, no server-side copy. That is a trade-off, not a feature: nothing to sign up for, but clearing your site data clears your history. Export a backup from Settings before switching machines — backups carry your sessions, so solves land back where they were recorded.
Creator of CubeBloom
I spent months stuck at the same average without knowing which part of the solve was costing it. Every timer told me I averaged 19 seconds; none told me where those seconds went.
So I built the thing I wanted: it measures every phase, shows you where the time actually goes, and hands the reading of it to a coach that has seen all of your solves rather than the last one.
The tips and drills draw on J Perm, CubeSkills and SpeedCubeDB, each credited on the page that uses them. Smart-cube support is built on gan-web-bluetooth. CubeBloom is not affiliated with any of them, or with the WCA.