SplitBae

Offline-first bill splitting that feels fast, private, and “native where it matters”.

Why SplitBae?

SplitBae is built as a Perfect Local Utility:

• Offline-first by design: your bill data lives locally (SQLite via Drift, with an optional SQLCipher layer).
• Encrypted local storage: when encryption is enabled, sensitive data is protected at rest.
• Native OCR for Snap & Split: extract receipt line candidates using on-device OCR (ML Kit on Android, Vision on iOS), then let users correct directly in the UI.
• Rust-speed math: deterministic currency rules and split calculations live in Rust and are exposed to Flutter via flutter_rust_bridge.

Instead of outsourcing receipt understanding to a cloud LLM, SplitBae keeps the core workflow private, fast, and editable.

Key Features

• Snap & Split (Native OCR): take a photo or choose from the gallery, run on-device text recognition, parse candidate lines, and edit before saving. Native OCR failures never block manual entry.
• Encrypted Local Storage (SQLCipher): at-rest encryption with a safe migration path and clear user controls.
• Rust-Speed Math: all business logic and currency math are implemented in Rust (rust/src/api/simple.rs) and consumed by Flutter.
• Per-line assignment: each receipt line can be split among a chosen subset of participants (empty assignment means “everyone”).
• Manual backups: export or import a .sb_backup file from Settings so users can move local data safely.

Technical Architecture

SplitBae keeps responsibilities sharp:

• Rust owns deterministic rules. Flutter delegates split math and money encoding/decoding to Rust via flutter_rust_bridge.
• Flutter focuses on UX, state orchestration (Riverpod), persistence (Drift), and calling the native OCR platform channels.

Rust ↔ Flutter bridge

flutter_rust_bridge matters because it gives you a reviewable, typed boundary:

• Rust stays unit-testable and deterministic for correctness.
• Flutter stays responsive by offloading compute-sensitive logic to Rust.
• Contributors can reason about “what changed” by looking at explicit FRB surfaces (#[flutter_rust_bridge::frb]).

Monorepo

This repository is intentionally single-repo:

• lib/ is the Flutter app
• rust/ is the Rust core (split logic exposed via FRB)

Keeping both parts together makes it harder for behavior to drift between UI and math.

Getting Started

Prerequisites

• Flutter (stable)
• Rust toolchain (rustup) for rust/

Setup

flutter pub get
flutter gen-l10n

cd rust && cargo check && cd ..

# if you changed Rust FRB API (types/functions annotated with #[flutter_rust_bridge::frb])
flutter_rust_bridge_codegen generate

flutter run

Contributing

See CONTRIBUTING.md.

License

Apache License 2.0. By contributing, you agree your contributions are under the same license.