SmallTalk

SmallTalk is a minimal, modern, friends and family focused Android messenger. Heavily inspired by Whatsapp and Signal, powered by Matrix.

Project mantra

• Tiny app size - currently 1.80mb~ when provided via app bundle.
• Focused on reliability and stability.
• Bare-bones feature set.

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Feature list

• Login with Matrix ID/Password
• Combined Room and DM interface
• End to end encryption
• Message bubbles, supporting text, replies and edits
• Push notifications (DMs always notify, Rooms notify once)
• Importing of E2E room keys from Element clients
• UnifiedPush
• FOSS variant
• Minimal HTML formatting
• Invitations
• Image attachments

Planned

• Device verification (technically supported but has no UI)
• Room history
• Cross signing
• Google drive backups
• Changing user name/avatar
• Room settings and information
• Exporting E2E room keys
• Local search
• Registration

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Technical details

• Built on Jetpack compose and kotlin multiplatform libraries ktor and sqldelight (although the project is not currently setup to be multiplatform until needed).
• Greenfield matrix SDK implementation, focus on separation, testability and parallelisation.
• Heavily optimised build script, clean cacheless builds are sub 10 seconds with a warmed up gradle daemon.
• Avoids code generation where possible in favour of build speed, this mainly means manual DI.
• A pure kotlin test harness to allow for critical flow assertions Smoke Tests, currently Linux x86-64 only.

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Building

Debug .apk

./gradlew assembleDebug

Release (signed with debug key) .apk

./gradlew assembleRelease

Unsigned release .apk

./gradlew assembleRelease -Punsigned

Unsigned release (FOSS) .apk

./gradlew assembleRelease -Punsigned -Pfoss

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Data and Privacy

• Messages once decrypted are stored as plain text within SmallTalk's database. Always encrypted messages comes at the cost of performance and limits features like local search. If maximum security is your number priority, SmallTalk is not the best option. This database is not easily accessed without rooting or external hardware.

• (Not yet implemented and may be configurable) Images once decrypted are stored in their plain form within the devices media directories, organised by room metadata.

• Push notifications contain no sensitive data by using the event_id_only configuration. Push notifications are used as a push to sync mechanism, where the on device sync fetches the actual contents.

• Passwords are NEVER stored within SmallTalk.

• SmallTalk does not explicitly talk to servers other than your home-server or track what you do. *

  • * There is no SmallTalk server capturing data from the application however the Google variant likely includes transitive telemetrics through the use of Firebase and Google Play Services integrations.

• SmallTalk is completely free and will never feature adverts or paid app features.

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SmallTalk comes in two flavours, Google and FOSS

Google

• Available through the Google Play Store and Github Releases.
• Automatic crash and non fatal error tracking via Firebase Crashlytics.
• Push notifications provided through Firebase Cloud Messaging.

FOSS

• Available through a self hosted F-Droid Repository and Github Releases.
• No Google or Firebase services (and their transitive telemetrics).
• No crash tracking.
• No push notifications by default, a separate UnifiedPush distributor is required.

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Repositories

SmallTalk is split into multiple repositories through git submodules.

small-talk

• The main repository, responsibile for rendering data into screens and generating the android application artifact.

chat-engine

• All things chat and matrix, where the vast majority of business logic sits.
• Pure kotlin with no UI.

conventions

• Reusable gradle plugins for modular android projects

screen-state

• Reusable state management and generic screen flow components.
• Wrapper around android's ViewModel focused on testability.

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Join the conversation @ https://matrix.to/#/#small-talk:iswell.cool