#Backend Development

Backend development guide for eval_752.

#Tech Stack

• FastAPI 0.115 - Web framework
• SQLAlchemy - ORM
• Alembic - Database migrations
• Celery - Async task queue
• LiteLLM - LLM provider integration
• Pydantic v2 - Validation
• structlog - Structured logging

#Project Structure

backend/src/eval_752/
├── app/           # FastAPI routes, dependencies
├── core/          # Config, logging, security
├── domain/        # Business models
├── infra/         # Database, external clients
├── services/      # Business logic
├── workers/       # Celery tasks
└── security/      # Encryption, API keys

#Development Setup

cd backend
uv sync --extra dev
uv run uvicorn eval_752.app.main:app --reload

#Quality Standards

Linting: ruff

uvx ruff check
uvx ruff format

Type Checking: mypy strict

uv run mypy --strict

Testing: pytest with 95% coverage

uv run pytest --cov --cov-fail-under=95

See Testing Guide for details.

#Key Patterns

• Business logic in services/, not routes
• Dependency injection via FastAPI
• Pydantic for validation
• Structured logging with context
• Async where beneficial
• Locale negotiation via middleware plus translated API errors

For localization conventions, see Internationalization.

For complete setup, see Contributing Guide.