fastapi-backend-overview

Implement FastAPI Router-Service-Repository layers with async SQLAlchemy and Pydantic v2.

3|Updated Jan 20, 2026

Search Tags:#architecture #fastapi #design-principles #pydantic-v2 #async-sqlalchemy #3-layer #backend-design

Ready to run

npx skills add https://github.com/agusmdev/burntop --skill fastapi-backend-overview

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: fastapi-backend-overview
Source: https://github.com/agusmdev/burntop/tree/main/.claude/skills/fastapi-backend-overview
Command: npx skills add https://github.com/agusmdev/burntop --skill fastapi-backend-overview

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This skill provides a clear blueprint and guidelines to implement a FastAPI 3-layer architecture, ensuring consistent separation of Router, Service, and Repository layers, async data access, and strong typing.

Core Features & Use Cases

3-layer architecture guidance: Router (API), Service (Business Logic), Repository (Data Access) with clear boundaries.
Tech stack standards: Async SQLAlchemy, Pydantic v2, Alembic migrations, and structured error handling.
Use Case: A new backend project can be scaffolded with standard architecture, or an existing codebase can be refactored to align with the pattern, enabling architecture reviews and faster onboarding.

Quick Start

Review the architecture overview, align your project structure to Router/Service/Repository, and apply the design decisions and best practices across modules.

Frequently Asked Questions about fastapi-backend-overview

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I structure a FastAPI backend with clear separation of concerns?▼

A FastAPI 3-layer architecture enforces separation of concerns by dividing code into Router for API endpoints, Service for business logic, and Repository for data access. This enforces strict boundaries, type safety, and asynchronous patterns across your project modules.

What is the best way to organize a FastAPI project using async SQLAlchemy and Pydantic v2?▼

The best way to organize a FastAPI project with async SQLAlchemy and Pydantic v2 is implementing a 3-layer architecture. This enforces strict separation of concerns, type safety, asynchronous data access, and structured error handling across the project.

Can I refactor an existing FastAPI codebase into a 3-layer architecture?▼

Yes, you can refactor an existing FastAPI codebase into a 3-layer architecture. This blueprint applies to projects at any stage, enabling architectural refactors that align your code with Router, Service, and Repository boundaries for faster onboarding and easier reviews.

Does the FastAPI 3-layer architecture pattern support Alembic migrations?▼

Yes, the FastAPI 3-layer architecture pattern supports Alembic migrations. The tech stack standards include async SQLAlchemy, Pydantic v2, Alembic migrations, and structured error handling to maintain strong typing and consistent data access.

When do I need to use a 3-layer architecture in my FastAPI backend?▼

You need a 3-layer architecture in your FastAPI backend when clear separation of Router, Service, and Repository is required. It is essential for projects requiring strict separation of concerns, type safety, and structured error handling at any development stage.