CruxCoach — Open-source Android app for Kilter Board, MoonBoard & Tension Board

What CruxCoach does

One app for every board you climb — open source, no account, no user tracking, and your personal data never leaves your device unless you say so.

Browse every board's catalogue

Kilter, MoonBoard and five more boards — 650,000+ climbs in total. Filter by grade, angle, quality, move count, setter. Works offline once the board database is synced.

Light up holds via Bluetooth

Direct BLE to your Kilter Board, MoonBoard, Tension Board and more. Pick custom colors per role — start, hand, foot, top — on every board except the MoonBoard, whose LED kit has fixed colors.

Set and share your own climbs

Create your own problems on any of the seven boards and publish them to the CruxCoach community over Nostr — no central server holding them, no gatekeeper.

Local, encrypted logbook

Sends, attempts, opinions, sessions — all stored on your device in an SQLCipher database. Never leaves unless you ask.

Share with climbers nearby

Other CruxCoach users at the same board see your current climb over Bluetooth — and you see theirs. No internet, no accounts.

Your training history, portable

Bring your history with you — for the old Aurora app before its March 2026 shutdown, import the JSON export requested from Aurora; for the current official app, connect your Kilter account directly in CruxCoach. From there your data stays portable: export to JSON, or turn on automatic encrypted backup only you can restore.

CruxCoach climb detail screen showing climb name, grade, stats, and the holds marked on a board diagram — Climb detail — grade, stats, and the hold sequence at a glance

CruxCoach logbook view showing logged sends and attempts — Local logbook — every send and attempt stays on your device

Why CruxCoach exists.

On 26 March 2026, Aurora's previous Kilter app was removed from the app stores, temporarily cutting climbers off from playlists, logbooks and draft climbs. A current official Kilter Board app is available again, but the interruption prompted an important question: why does my training data live only on someone else's server in the first place?

CruxCoach is one answer to that question. Your training history sits encrypted on your phone. Your identity is a Nostr keypair you control, not an account someone can revoke. Choose the board catalogues you need and sync their content-addressed data to your device — once you have them, you have them. And the whole thing is open source under the GPL: anyone can audit it, fork it, run it.

It started narrow on purpose: Kilter only, Android only. With 0.2.0 it speaks the whole family — Kilter, MoonBoard, Tension, Grasshopper, Decoy, So iLL and Touchstone. Still Android only, still yours.

Coming from the old app? The Kilter app alternative & migration guide walks you through getting your logbook back.

Privacy by architecture, not by promise

Privacy claims are easy. CruxCoach is built so the privacy holds even if we're lying about it.

No accounts, no signup. Your identity is a Nostr keypair generated on first launch, stored in the Android Keystore.
No Google Play Services. Works on de-Googled phones — GrapheneOS, /e/OS, LineageOS without GApps.
Encrypted local storage. Personal data lives in an SQLCipher database. Encryption key never leaves your device.
No user tracking, ads, or third-party analytics SDKs. Personal and training data is never sent to analytics. Current release 0.2.1 sends no app-analytics event. The upcoming 0.2.2 release will add a first-party count only after an updater download passes its SHA-256 and signer checks; it contains only target version and source, never a device, installation, account, Nostr, or user identifier.
No central account or training-data server. The app uses public Nostr relays and Blossom servers run by independent operators. The website's separate first-party counter stores only daily page-view, install-click, and same-tab Zapstore→APK fallback aggregates.
Verifiable open-source builds. Code on Codeberg, releases signed, auto-updater pins the developer key on first install.

Runs on de-Googled Android — no Play Store, no Play Integrity

If your phone ships without Google services, CruxCoach is built for you: nothing it does depends on Google.

No Google Play Services. CruxCoach calls no GMS APIs and runs fully on GrapheneOS, CalyxOS, /e/OS and LineageOS without GApps.
Install without the Play Store. Get it from Zapstore or use the one-click APK download, which automatically selects the available verified Codeberg or Zapstore copy. CruxCoach is not on Google Play and never requires it.
Updates without Google. The optional in-app updater pulls signed APK releases straight from Codeberg with TOFU certificate pinning — no Play Store and no Play Integrity check. On Zapstore installs it disables itself and lets the store update.

Install

Three ways to install today — all of them without Google.

Zapstore recommended

Privacy-respecting, Nostr-native Android store. Verifies developer signatures. Auto-updates.

Open in Zapstore

Direct APK

One button downloads the signed APK from whichever verified source is currently available: Codeberg or its identical, content-addressed Zapstore mirror.

Download APK

Obtainium

Open-source installer that tracks a project's own releases and keeps them updated — no store in between. The button below opens Obtainium with CruxCoach prefilled; if it is not installed yet, add the source by hand with https://codeberg.org/CruxCoach/CruxCoach.

Add to Obtainium

Frequently asked questions

The questions people actually ask before installing.

Is CruxCoach an alternative to the official Kilter Board app?

Yes. CruxCoach is an independent, open-source Android app for app-controlled training boards — Kilter, MoonBoard, Tension and more — not affiliated with Kilter, LLC, Moon Climbing or Aurora Climbing. It browses climbs, lights up the holds over Bluetooth and logs your ascents on your own device, with no account and no Google services required. It is licensed under the GPL-3.0 and focuses on Android, rather than trying to cover every platform.

How do I import data from the old and current Kilter apps?

Use the route that matches the app holding your history. For the old Aurora-operated app before its 26 March 2026 shutdown, request a personal data export from Aurora, then open Settings → Migrate from Aurora / old Kilter app and import the JSON file. For the current official Kilter app since March 2026, open Settings → Kilter Board Account → Connect Kilter Account, sign in and choose Import once or Sync continuously; no Aurora export is needed. Imported data stays encrypted on your device.

Does it work without a Google account or Google services?

Yes. CruxCoach needs no account and no Google Mobile Services. Your identity is a Nostr keypair generated on first launch and stored in the Android Keystore. It runs on de-Googled phones such as GrapheneOS, /e/OS and LineageOS without GApps, on Android 8.0 or later with Bluetooth LE. There is no user tracking or third-party analytics SDK. Current release 0.2.1 sends no app-analytics event. The upcoming 0.2.2 release will add one identifier-free aggregate event, sent only after the optional in-app updater has fully downloaded an APK and verified its SHA-256 and signing certificate.

Which boards and Android versions does CruxCoach support?

CruxCoach drives seven board systems interactively on Android 8.0 or later with Bluetooth LE: the Kilter Board (all sizes and adjustable angles), the MoonBoard (2016, Masters 2017, Masters 2019, Mini 2020 and 2024), and the Tension, Grasshopper, Decoy, So iLL and Touchstone boards. Browse each board's catalogue, filter by grade, angle, quality, move count and setter, then light it up over Bluetooth. The separate board map is broader still: it also plots Aurora and 12 Climb installations as location-only layers.

Does CruxCoach work with the MoonBoard?

Yes. CruxCoach is a free, open-source MoonBoard app for Android: browse the MoonBoard problem catalogue with the same filters as the Kilter catalogue, open a problem and light up the holds on your physical board over Bluetooth. Five configurations are supported — MoonBoard 2016, Masters 2017, Masters 2019 and MoonBoard 2024 (each at 25° and 40°), plus Mini 2020 (40°). It needs no account and no Google services.

Where can I find a Kilter Board or MoonBoard near me?

CruxCoach publishes a free interactive board map covering 2,700+ venues across nine board systems in 80+ countries — Kilter Board, Tension Board, MoonBoard and six more — filterable by board type, country and wall details.

One open-source Android app for all your climbing boards.