FastAPI Development Services | Python API Experts | Zargham Labs LLC

FastAPI has become the default choice for production Python APIs — and for good reason. It’s faster than Flask, more structured than Django REST Framework for pure API work, and ships with automatic OpenAPI documentation out of the box. At Zargham Labs LLC, FastAPI is the backbone of every backend we build, including our own flagship product Messenjo.

When you hire us for FastAPI development services, you’re getting engineers who use FastAPI in production daily — not someone who picked it up to win a contract.

Our FastAPI Development Services

• REST API Development — Well-structured, versioned APIs with proper HTTP semantics, pagination, filtering, and error handling. Auto-generated OpenAPI docs included.
• Async Endpoints & Background Tasks — FastAPI’s async support is its superpower. We build non-blocking endpoints and background task pipelines using Celery + Redis for heavy workloads.
• Authentication & Authorization — JWT token authentication, refresh token rotation, OAuth2 flows, role-based access control (RBAC). Production-grade security from day one.
• Database Integration — SQLAlchemy async ORM with PostgreSQL, PgBouncer connection pooling, Alembic migrations. Your data layer is designed to survive growth.
• Third-Party API Integration — WhatsApp Cloud API, Stripe, PayPal, Twilio, SendGrid, HubSpot, and custom webhooks. We’ve integrated with dozens of external services.
• Microservices & API Gateway — For larger projects, we design service-oriented architectures with Traefik as the API gateway and Docker for container orchestration.

Why Choose Zargham Labs for FastAPI Development

• Production Experience — We run FastAPI in production for Messenjo, handling real traffic. We know where the edge cases are and how to handle them.
• Full-Stack Context — We build the FastAPI backend alongside the Next.js frontend and PostgreSQL database. No interface mismatch between layers.
• Performance-First Design — Async endpoints, connection pooling, caching strategies, and query optimization are built in from the start — not added after performance problems appear.
• Clean Code Standards — Type hints throughout, Pydantic models for request/response validation, dependency injection for testability. Code you can hand to another developer.
• Fixed-Price Delivery — We scope FastAPI projects clearly and deliver on budget. No hourly billing ambiguity.

Our FastAPI Tech Stack

• Framework: FastAPI 0.100+, Pydantic v2
• ORM: SQLAlchemy 2.0 (async), Alembic migrations
• Database: PostgreSQL 15, Redis, PgBouncer
• Task Queue: Celery, RedBeat, Flower (monitoring)
• Auth: python-jose (JWT), passlib (bcrypt), OAuth2
• Testing: pytest, pytest-asyncio, httpx (async test client)
• Deployment: Docker, Docker Compose, Traefik, Linux VPS
• Monitoring: Prometheus metrics, Grafana dashboards, Sentry

FastAPI Development Process

1. API Design First — We design the full API schema before writing code. Endpoint structure, data models, auth flows, and error responses are agreed upon upfront.
2. Core Build — Implement endpoints, database models, authentication. Every endpoint has tests before it’s considered done.
3. Integration & Background Tasks — Wire up third-party APIs, implement Celery workers for async jobs, connect to message queues.
4. Performance & Security Hardening — Load testing, query optimization, security review, rate limiting, input validation.
5. Documentation & Deployment — OpenAPI docs finalized, Docker containerization, deployment to your VPS or cloud provider.

Frequently Asked Questions

How does FastAPI compare to Django REST Framework?

FastAPI is faster (both in performance and development speed for pure API work), has better async support, and generates documentation automatically. Django REST Framework is more appropriate when you need Django’s ORM ecosystem, admin panel, or existing Django integrations. For greenfield SaaS APIs, FastAPI is almost always the better choice.

Can you migrate our existing Flask/Django API to FastAPI?

Yes. We’ve done migrations from both Flask and Django to FastAPI. The approach depends on your existing codebase — we assess during the discovery call and provide a migration plan before starting.

Do you provide the API documentation?

FastAPI generates Swagger UI and ReDoc documentation automatically from your code. We also provide additional developer documentation covering authentication flows, common use cases, and integration examples — especially important if other teams will be consuming your API.

Start Your FastAPI Project

Tell us what you need to build. We’ll tell you how FastAPI fits, what the architecture should look like, and what it will cost.

Book a free technical discovery call →

Zargham Labs LLC · FastAPI & Python API Development · US-Registered · zarghamlabs.com