Example: Multi-Tenant API Service (FastAPI + enzu)

[teilomillet]

Goal

Production SaaS example showing how to integrate enzu into a FastAPI service with per-customer budgets.

Use Case

Document analysis API with multiple customers, each with their own budget limits.

What It Demonstrates

• FastAPI integration - REST endpoints with enzu execution
• Multi-tenant isolation - per-customer budget tracking
• Job queue pattern - async processing with delegation
• Observability - Prometheus metrics, structured logging
• Rate limiting - budget-aware request throttling
• Session management - customer context preservation

Deliverables

• examples/api_service/
  • main.py - FastAPI app with endpoints
  • models.py - Pydantic request/response models
  • budget.py - per-customer budget controller
  • worker.py - background job processor
  • docker-compose.yml - Redis + service setup
  • README.md - deployment guide, API docs
  • tests/ - integration tests
  • metrics.py - Prometheus exporters

Example Endpoints

POST /analyze - Submit document for analysis
GET /jobs/{id} - Check job status
GET /metrics - Prometheus metrics
GET /health - Health check

Success Criteria

• Runs with docker-compose
• Multiple customers isolated
• Budget enforcement per customer
• Prometheus metrics exposed
• Clean error handling + typed outcomes

Target Audience

SaaS companies, API service builders

Estimated Effort

Large (3-4 days)