# ADR-001: Go + Rust + React Architecture (Rust Services)

**Reference**: CLN-08  
**Date**: 2026-02-22  
**Status**: Accepted

## Context

Veza is a music collaboration platform with a polyglot architecture:

- **Go**: Backend API (REST, business logic, authentication)
- **Rust**: Chat server and stream server (real-time, audio processing)
- **React**: Frontend application

The platform requires different capabilities across services: high-throughput REST APIs, real-time WebSocket communication, and performance-critical audio transcoding. Each language was chosen for its strengths in specific domains.

## Decision

The Go + Rust + React architecture is adopted with clear boundaries:

### When to Use Rust

- **Audio transcoding**: FFmpeg integration, format conversion, streaming pipelines
- **Real-time stream processing**: Low-latency audio/video handling
- **Performance-critical paths**: Where predictable latency and memory safety matter

### When to Use Go

- **REST API**: HTTP endpoints, request handling, routing
- **CRUD operations**: Database access, business logic
- **Authentication**: Session management, token validation, authorization
- **General backend services**: Where developer productivity and ecosystem matter more than raw performance

### When to Use React

- **Frontend**: User interface, state management, client-side interactions

## Consequences

### Positive

- Each service uses the most appropriate language for its domain
- Rust provides safety and performance for stream server (FFmpeg, transcoding)
- Go enables rapid development for API and business logic
- React ecosystem supports rich frontend development

### Negative

- **Operational complexity**: Three languages increase deployment, monitoring, and debugging overhead
- **Harder onboarding**: New developers must learn multiple stacks
- **Maintenance cost**: Tooling, dependencies, and expertise required for each language

### Future Direction

The chat server will be rewritten in Go in v0.501. Rust adds complexity for chat without proportional benefit; Go's goroutines and channels are well-suited for WebSocket handling, and the team is already proficient in Go. See [ADR-002](ADR-002-chat-server.md) for details.