A free, open-source Tension Board app for Android

CruxCoach browses the Tension Board catalogue offline and lights up the holds on your physical board over Bluetooth — with no account, no subscription, and no Google services. The same app also drives your Kilter and MoonBoard sessions.

Install CruxCoach

Free, no strings attached. The recommended route is Zapstore, a privacy-respecting Android store that verifies developer signatures and auto-updates; the signed APK from Codeberg works just as well, with the in-app updater handling future releases. One APK button uses a first-party selector to choose the currently available verified Codeberg copy or its identical, content-addressed Zapstore mirror.

Download CruxCoach

Free. No account. Verifiable signed builds. Android 8.0+.

What CruxCoach does with the Tension Board

Browse about 132,200 climbs offline. Sync the catalogue once, then filter it with no connection at all — by grade, angle, quality, move count and setter.
Light up the holds over Bluetooth LE. Open a climb and send it straight to the board; no phone-to-cloud round trip in between.
Set and share your own climbs over Nostr, with no central server holding them.
One app for every board. The same install also drives Kilter, MoonBoard, Grasshopper, Decoy, So iLL and Touchstone.
Encrypted local logbook. Your sends, attempts and sessions stay on your device in an SQLCipher database.

No account, no subscription, no Google

The official Tension Board app, published by Aurora Climbing, asks you to create an account and puts part of its functionality behind a paid subscription. CruxCoach takes a different route: it creates no conventional account, charges nothing, and has no Google Mobile Services dependency.

That makes it suitable for de-Googled Android setups such as GrapheneOS, CalyxOS, /e/OS or LineageOS without GApps. Your identity is a Nostr keypair generated on first launch and kept in the Android Keystore — nothing anyone can revoke. There is no user tracking and no third-party analytics SDK; website analytics are limited to the anonymous aggregate counters described in the privacy notice.

Find a Tension Board near you

The CruxCoach board map plots 353 Tension Board venues worldwide alongside every other board system, filterable by board type and country. Search for a gym or a city, or use the location button to see what is closest to you — the whole map runs client-side, with no geocoder and no account.

What CruxCoach is — and isn't

CruxCoach is a community project, not affiliated with Tension Climbing or Aurora Climbing; "Tension Board" is used only to describe hardware compatibility. It is Android-only (8.0 or later, with Bluetooth LE) and open source under the GPL-3.0 — anyone can audit, fork and build it from Codeberg. If you need an iOS app, this isn't it.