Slacklet - A Slack Client for WearOS

Slacklet is a standalone Slack client for wearOS. This app is fully independant from your other Slack devices. This is done via internal Slack APIs to demostrate the capabilities outside of it's normal usage.

I've built this because the official Slack app has no wearOS version, and I've always felt the need for one. Originally, I was planning on just using Public APIs to create a clone on my watch, but it ended up having a slew of issues including lag, missing features etc.

• Channel and DM lists, with unread and mention badges
• Reading conversations, including threads
• Sending messages
• Reactions (synced from your slack devices)
• An Activity feed for mentions, replies and reactions
• Search
• Custom emoji rendering
• Push notifications, with inline reply from the notification
• Slack markdown, permalink previews and DND

Huddles, Canvas's and any AI features have not been built in yet and are planned for the v2 release.

Slack  <--- HTTPS ---  watch
  |
  |  Events API (signed)
  v
relay (Ktor, self-hosted)  --- FCM --->  watch

The watch calls Slack directly for everything it reads and writes. The relay exists only because Slack has no way to push to a device: it receives Events API callbacks, works out which messages should wake your watch, and sends a data-only FCM message containing the notification text.

A signed-in watch enrolls itself with the relay on first launch. It sends a device id, a capability digest and its FCM token, and the relay establishes who you are by asking Slack (auth.test) rather than trusting anything in the request. Slack session tokens are never stored on the relay.

• Wear OS 3 or newer (minSdk 30); this was developed and tested against Wear OS 7 (API 37)
• JDK 17
• A Firebase project, for push
• A host to run the relay on, if you want notifications

./gradlew :app:assembleDebug
adb install -r app/build/outputs/apk/debug/app-debug.apk

./gradlew test
./gradlew koverHtmlReport

If you want to run it on an emulator:

avdmanager create avd -n SlackWear7 \
  -k "system-images;android-37.0;android-wear-signed;arm64-v8a" -d wearos_large_round

Then set hw.lcd.circular=yes in ~/.android/avd/SlackWear7.avd/config.ini. avdmanager does not set it, and without it you get a square screen with none of the round crop or bezel transformations, which makes the whole UI look wrong.

Notifications need two things you have to provide yourself: a Firebase project and a host for the relay.

1. Create a Firebase project and add an Android app for com.scooter.slackwear (and com.scooter.slackwear.debug if you want push in debug builds). Put the resulting google-services.json in app/. It is git-ignored.
2. Create a Slack app, subscribe to message events on behalf of users (not the bot section), and point the Request URL at your relay's /slack/events.
3. Deploy the relay and give it your Slack signing secret and a Firebase service account key.

Lato is used under the SIL Open Font License. Colour values are Slack's published design tokens.

This project is not affiliated with, endorsed by, or supported by Slack.

AI was used to assist in the decompliation steps and the writting of parts of this codebase. All code written by an LLM was monitored and reviewed with passing tests.