Polyphony

Polyphony is a real-time communication platform with a Rust backend and a Flutter client.

What this project includes

• Backend API for auth, identity, messaging, servers/channels, and voice session flows
• Domain layer for business entities and invariants
• Storage layer with migrations and persistence implementation
• Flutter client for cross-platform user experiences
• Infrastructure as code for cloud provisioning and environment setup
• BDD feature coverage for behavior-focused acceptance tests

High-level technology choices

Backend (Rust)

• Language/runtime: Rust
• Architecture: multi-crate workspace with clear boundaries:
  • backend-api: transport, DTOs, routing, OpenAPI wiring
  • backend-domain: core domain entities and rules
  • backend-storage: persistence and database migrations
• Testing: unit tests + BDD acceptance scenarios in features/ and backend-api/tests/

Why this choice:

• Strong type safety and performance for network services
• Clear separation between API, domain, and persistence concerns
• Reliable refactoring in a growing codebase

Client (Flutter)

• Framework: Flutter/Dart
• Target platforms: web + desktop/mobile foundations via a shared codebase
• Client structure: feature-oriented modules under apps/flutter_client/lib/

Why this choice:

• Single UI codebase across platforms
• Fast iteration for UX and state-driven interfaces
• Good fit for shared product behavior across targets

Infrastructure & operations

• Containerized local dependencies: Docker Compose (docker-compose.local.yml)
• Real-time media/config support: LiveKit local config (livekit.local.yaml)
• Infrastructure as code: Pulumi (pulumi/)

Why this choice:

• Reproducible local environments
• Explicit, versioned infrastructure changes
• Consistent developer setup and deployment workflows

Repository layout

apps/flutter_client/   # Flutter application
crates/                # Experimental/support Rust crates
backend-api/           # API crate
backend-domain/        # Domain crate
backend-storage/       # Storage crate + migrations
features/              # BDD feature files
pulumi/                # Infrastructure as code

Getting started (local)

1. Start local dependencies (for services that require containers).
2. Run backend tests from the repository root:
   • cargo test
3. Run Flutter tests from the Flutter app directory:
   • flutter test

See also:

• docs/local-dev.md
• docs/production-deploy.md
• apps/flutter_client/README.md
• pulumi/README.md