Backend & Cloud Engineering
Python & FastAPI Development
Fast, well-tested backend services that hold up under real load.
- Typical timeline
- 4-12 weeks depending on scope
- Category
- Backend & Cloud Engineering
- Engagement
- Fixed-scope phases
- You receive
- Code, data & documentation
Overview
FastAPI is our default choice for new backend work. It gives us type checking at the boundary, validation that cannot be skipped, automatically generated API documentation and performance that comfortably handles the load a growing business produces.
The backend is the part that breaks at the worst moment
Backends assembled quickly tend to have no tests, no input validation and no documentation. They work until traffic rises or an edge case appears, then fail in ways that are hard to diagnose because nothing was logged. Each subsequent change carries risk, so development slows to a crawl.
You will recognise this if
- Changes to the backend regularly break something unrelated
- There is no documentation of what the API endpoints actually accept
- Errors appear in production with no logs explaining what happened
- Performance degrades badly under concurrent use
What you get out of it
The difference this makes
Validation at the boundary
Every request is validated against a schema before it reaches business logic, which removes an entire class of runtime failures and security issues.
Documentation that cannot go stale
OpenAPI documentation is generated from the code itself, so front-end developers and integration partners always see the current contract.
Changes you can make confidently
Automated tests over business rules mean a change can be shipped without a week of manual regression checking.
Performance headroom
Async request handling and proper connection pooling mean a modest server handles substantial concurrency.
What we build
- FastAPI services with Pydantic schemas and full type annotations
- Automatically generated OpenAPI and Swagger documentation
- Authentication and authorisation: JWT, OAuth 2.0, API keys, role-based access
- Background jobs and scheduled tasks with Celery or ARQ
- Database access through SQLAlchemy with versioned Alembic migrations
- Structured logging, request tracing and error tracking
- Automated test suite with pytest, covering business rules and edge cases
- Rate limiting, request size limits and input sanitisation
- Containerised deployment with health checks and graceful shutdown
How it gets used
A mobile app needing a backend
A typed API with authentication, push notification support and admin endpoints, documented well enough for an app developer to work independently.
AI features behind a clean interface
Model calls, retrieval, queuing and cost controls kept server-side behind a stable API, so provider changes never require front-end work.
A business replacing an unreliable backend
Endpoints are rewritten behind the existing interface and migrated gradually, so the front end keeps working throughout.
Technology we typically use
You do not need to care about this list — but your next developer will.
- Python 3.12+
- FastAPI
- Pydantic
- SQLAlchemy
- Alembic
- PostgreSQL
- Celery / Redis
- pytest
- Docker
Timeline: Typically 4-12 weeks depending on scope
Questions
Python & FastAPI Development — common questions
Something else on your mind? Ask us directly — it is usually faster than reading.
Why FastAPI rather than Django or Flask?
Can you work with our existing Python codebase?
How do you handle database migrations safely?
Related services
Businesses that need this often need one of these as well.
Thinking about python & fastapi development?
Tell us about your situation. We will tell you whether this is the right service, what it would involve, and roughly what it would cost.