Founders and CTOs frequently ask me: "Should we build our backend in Python Django, Python FastAPI, or Go (Golang)?" Having architected high-scale production systems in all three over the past 15+ years, here is how I help clients choose—and combine—the right stack.
1. When to Choose Django & Django REST Framework
Choose Django when your product has rich relational domain models, multi-tenant permissions, complex back-office admin workflows, and rapid B2B SaaS iteration needs. See Building a Custom BI Engine in Django ORM.
2. When to Choose Python FastAPI + SQLAlchemy 2.0 (`asyncpg`)
Choose FastAPI for asynchronous AI/LLM streaming gateways, high-concurrency webhook receivers, and ML inference microservices where Pydantic v2 validation and non-blocking `asyncio` shine. See Architecting Asynchronous Microservices with FastAPI.
3. When to Choose Go (Golang)
Choose Go for unified edge API gateways, ultra-low-latency AWS Lambda functions (Go vs. Python on AWS Lambda), PCI-DSS payment routers, and closed-loop financial ledgers.