CruxCoach

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

Kilter, MoonBoard, Tension and more — browse climbs, light up holds, log your sessions, without an account, without Google services, without anyone tracking your training.

  • 7 boards, one app
  • Custom hold colors
  • Encrypted local logbook
  • German & English UI
Get on Zapstore Download APK

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

Browse climbs in CruxCoach — list of climbs filterable by grade, angle, and quality

Existing catalogue and Bluetooth hold-lighting on all seven boards:

Aurora and 12 Climb also appear on the board map as location-only layers.

What CruxCoach does

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

Browse every board's catalogue

Kilter, MoonBoard and five more boards — 496,000+ 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.

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 — import an Aurora data export (ascents, attempts, circuits), or sign in once with your Kilter account to pull your logbook directly. 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 Kilter app was pulled from the App Store and Play Store after a dispute between Aurora Climbing and Kilter, LLC. Tens of thousands of climbers lost access to their playlists, logbooks, and draft climbs overnight. The new official app shipped half-finished, and people started asking the obvious question: why does my training data live 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. The board database is content-addressed and downloaded to your device on first sync — once you have it, you have it. 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.

Privacy by architecture, not by promise

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

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.

Install

Two ways to install today. Two more coming.

Zapstore recommended

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

Open in Zapstore

Direct APK

Download the signed APK directly from Codeberg releases and install manually. The in-app updater handles future updates.

Latest release

F-Droid coming soon

Planned future channel — slowest to update but the broadest reach in FOSS-Android. No specific timeline yet.

Pending

IzzyOnDroid coming soon

Third-party F-Droid-compatible repo. Preserves the developer signature. Planned future channel.

Pending

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.

Can I get my old Kilter Board data back after the app was taken down?

Yes. Request a data export from Aurora, the operator of the old app, and they email you a JSON file. In CruxCoach, open Settings → Migrate from Aurora to import it: your ascents, attempts, circuits and bid history land in your local logbook, and re-importing the same file is safe. If you still have a working Kilter account, you can instead sign in once to import your logbook directly. Either way the data then lives 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 telemetry, no analytics and no third-party SDKs.

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 — the 2024 set currently carries community-contributed problems), 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 (40°), Masters 2017, Masters 2019 (25° and 40°), Mini 2020 and MoonBoard 2024. It needs no account and no Google services. The MoonBoard 2024 set currently ships community-contributed problems rather than the full catalogue.

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.

For developers

CruxCoach is GPLv3, written in Kotlin Multiplatform with a Jetpack Compose Android frontend. Issues and PRs live on Codeberg.

git clone https://codeberg.org/CruxCoach/CruxCoach.git
cd CruxCoach
bash scripts/setup_dev_env.sh
./gradlew :androidApp:assembleDebug
Source code Issue tracker Contributing guide Security policy