# Gearslip
An Android Auto alternative built for everyone.
[](https://forthebadge.com)
[
](https://apps.obtainium.imranr.dev/redirect?r=obtainium://add/https://github.com/Seb3thehacker/gearslip)
Questions, ideas?
[Join the discussion on Matrix](https://matrix.to/#/!mf0_mgBd5KqKpc9FfX_wHp1jFCcwAtPrndIn_oGIyMk?via=matrix.org).
## Which cars work
Most cars work. Starting around 2020, some cars added newer security standards that reject
Gearslip's certificate, and Gearslip can't run in those cars.
## What Gearslip is
Gearslip is an Android Auto client for the phone. It speaks the Android Auto protocol
directly to a car head unit over USB, with no Google software in the path. Gearslip acts
as a Car App Library host: an app that ships a car interface hands Gearslip a template,
and Gearslip renders that template natively on the car screen. Nothing is mirrored from
the phone. For apps without a car interface, Gearslip offers a separate screen-sharing
mode.
| | |
|---|---|
|  |  |
| Apps sorted by kind. A check marks the ones that work. | Vela Maps navigating, with the player beside it. |
|  |  |
| ViVi Music in Gearslip's player. | A new message, read aloud at a tap, over the map. |
|  |  |
| The weather, your next event, and what you missed. | Browse the web while parked. |
## Features
- **Phone calls.** Dial from a keypad, or search your contacts, then confirm before the
call goes out.
- **Navigation.** Gearslip hosts real Car App Library map apps on the car screen.
Organic Maps, OsmAnd, and Flitsmeister work today. Vela runs, with rough
edges.
- **Music.** Browse, play, and queue tracks from a car-enabled media app, with a Now
Playing view, an Up Next queue, and lyrics. Type a search, and apps that accept one
play the best match.
- **The web.** A browser template with its own on-screen keyboard, for anything that
doesn't ship a car interface of its own.
- **Weather and the day ahead.** A dashboard screen shows the week's calendar next to
the current and coming weather.
- **Messages.** New messages appear as a small card on the car screen. Gearslip reads
each one aloud, and you reply by voice or with a quick reply. Music pauses while
Gearslip speaks or listens. Speech runs on the phone, so it needs no Google account.
- **Notifications.** Only messages, missed calls, alarms, and reminders interrupt you.
The rest wait on the dashboard.
- **Your apps, your order.** The launcher groups apps by kind: phone, maps, music,
messaging, and the rest. Press and hold an app to move it.
- **Car controls.** Steering wheel buttons, control knobs, and D-pads all work.
- **Themes.** Choose flat buttons or skeuomorphic ones that look like real keys.
## Status
- **The connection is wired only, for now.** Plug the phone into the head unit's USB port;
Gearslip does not yet offer a wireless option.
- **Setup walks you through it.** First launch asks for the Android Auto certificate,
then one permission at a time, each with a plain reason and an Allow or Skip. A help
screen inside the car answers anything setup didn't cover.
- **Templated apps work.** Gearslip renders all 16 template types that the Car App
Library defines, and it draws its own keyboard for search, sign-in, and text fields.
It has been tested against several real navigation and media apps.
- **Gearslip works with [LIVI](https://github.com/f-io/LIVI),** the open-source head unit
used in homemade car dashboards.
- **Some apps refuse Gearslip.** Spotify, Waze, and Google Messages use a version of
Google's car library that accepts only Android Auto itself. Spotify still plays through
Gearslip's own player.
- **Calls use the car's Bluetooth,** as they do in Android Auto. Pair the phone with the
car to hear calls through its speakers.
- **Audio reaches the car by capturing playback, not by mirroring the screen.** Android
shows a screen-share consent dialog for this, even though Gearslip never reads the
screen; it is the only way an ordinary app can capture another app's audio. The dialog
appears once per drive.
- **Gearslip needs no adb, root, or Shizuku.** Every feature relies on an ordinary
Android permission or an on-device consent dialog. The setup guide offers two optional
adb commands: one removes the audio dialog for good, and the other keeps notifications
visible while audio plays.
## Usage notes
Gearslip can send short notes that show which cars it works in. They stay off unless you
turn them on, in setup or in Settings.
- **When they go out.** When you open Gearslip, at most once a day, and after each drive.
Nothing runs in the background.
- **What they carry.** The Gearslip version, plus whatever you tick: the Android version
and whether the phone runs GrapheneOS, the phone model, whether a car connected that
day, and each car's head unit, model, year, screen size, and connection result.
Settings shows the exact note.
- **What they leave out.** Your name, accounts, location, contacts, messages, and
anything you type or play.
- **How phones are counted.** A random number counts each phone once. The server keeps
only a salted hash of it.
- **Where they go.** To Gearslip's server. Like any website, it sees your IP address when a
note arrives, and it doesn't store it.
Turn the notes off, and they stop at once.
## How Gearslip is made
Gearslip is my beloved child. I decide what it does and how it looks, and Claude writes nearly
all of the code. I test every change myself before it ships: in a real car, with both a
GrapheneOS phone and a stock Android phone, and on [LIVI](https://github.com/f-io/LIVI), the
open-source head unit software. I watch the phone's temperature too, so a new feature doesn't
cook it. Then I beg my friends to try it in their cars, so it works in as many makes, models,
and years as possible. If something breaks, that's on me, so please open an issue.
## Contributing
Bug reports from real cars help most, and pull requests are welcome.
[CONTRIBUTING.md](CONTRIBUTING.md) explains what to put in a report, which branch to work
on, and the one-time agreement you sign before your first pull request merges.
## Building
```
./gradlew :gearslip:assembleDebug
```
The APK lands at `build/Gearslip-debug.apk`.
A release build needs a signing key. Copy `keystore.properties.example` to
`keystore.properties`, fill in your own values, and run
`./gradlew :gearslip:assembleRelease`. Git ignores both the properties file and the
keystore. Without them, the debug build still works.
## Writing apps for Gearslip
[docs/BUILDING_APPS.md](docs/BUILDING_APPS.md) specifies how to write apps that Gearslip
can render: templated apps, media apps, and the Gearslip app protocol.
## How Gearslip talks to cars
Gearslip is an independent program, written to work with car head units. What it knows of
the protocol comes from public open-source projects such as
[aasdk](https://github.com/opencardev/aasdk) and open-android-auto, and it contains none
of Google's Android Auto code.
Gearslip ships without a certificate. On first launch you choose where yours comes from:
download the one the aasdk project publishes, or import a file of your own. The
certificate stays on your phone. Gearslip never uploads, backs up, or logs it.
## Trademarks
Android, Android Auto, Google Messages, and Waze are trademarks of Google LLC. Spotify is
a trademark of Spotify AB. Gearslip is not affiliated with, endorsed by, or sponsored by
any of these companies. All other names belong to their owners.
## License
Gearslip is licensed under AGPL-3.0; see [LICENSE](LICENSE). The author offers a separate
commercial license for private use outside the AGPL's terms; see [NOTICE.md](NOTICE.md).