FastAPI Development · Cardiff
FastAPI Development in Cardiff
Building APIs with FastAPI for Cardiff organisations, where the type annotations are not documentation — they are the validation and the specification. Declaring what an endpoint accepts produces the parsing, the error responses and the published schema from one definition, which removes the usual drift between what an API does and what it claims to do.
Why this comes up
The problem
The API documentation was written by hand, the endpoints have changed since, and consumers are building against something that no longer exists.
What you get
What we deliver
- Request and response models defined as types, so validation and docs stay aligned
- Blocking calls kept out of async endpoints, where they stall everything
- Synchronous work declared as such, so the framework runs it appropriately
- Dependency injection used for shared concerns rather than module-level state
- Generated schema published and used by consumers to generate their clients
- Background work handed to a queue rather than to background tasks in the request
Want this scoped for your business in Cardiff?
Thirty minutes, no charge, no sales script. You leave with a written summary of what fastapi development would actually involve — whether or not you use us.
Working in Cardiff
Wales
Cardiff has a significant broadcast and media sector alongside a large public-sector presence, and Welsh-language provision is a genuine requirement on public-facing work here rather than a nice-to-have.
Public sector and broadcast work is common, and bilingual provision is usually a requirement rather than an option.
Sectors we work with in Cardiff
- Media & Broadcasting
- Financial Services
- Public Sector
- Higher Education
- Sport
What we work with
Technologies and platforms
- FastAPI
- Python
- Pydantic
- PostgreSQL
Who we work with
Industries we serve
- SaaS businesses
- Research organisations
- Financial services
- Healthcare
- Technology companies
Why us
Why Cardiff businesses choose Asionis
- Projects typically launched within 4–8 weeks
- No long-term contracts required
- All team members UK-based
- Dedicated account manager and development team
- Transparent reporting with monthly performance metrics
- Scalable from startup to enterprise
How we work
- Step 1
Free consultation
A 30-minute call to understand the problem. You keep the written summary either way.
- Step 2
Proposal
Scope, timeline and a fixed price, in writing, before anything starts.
- Step 3
Build
Short cycles with regular check-ins, so you see progress rather than hear about it.
- Step 4
Launch and support
We handle the go-live and stay available afterwards.
Other services in Cardiff
Looking for the full picture? See our FastAPI Development services, everything we do in Cardiff or browse everything we do.
FastAPI Development in Cardiff — common questions
- What happens if we block inside an async endpoint?
- Everything waits. An asynchronous handler shares one event loop, so a synchronous database driver or a file read inside it stops every other request — and the fix is either an async client or declaring the endpoint synchronous so it runs elsewhere.
- Why declare an endpoint synchronous?
- Because the framework then runs it in a thread pool where blocking is safe. A handler using ordinary blocking libraries is better declared that way than made async, since a poorly written async handler is worse than a correctly declared synchronous one.
- Is the generated documentation good enough to publish?
- Generally yes, and it is the point. Because it derives from the same models that validate requests, it cannot drift — and consumers can generate typed clients from it, which removes a whole category of integration mistakes.
- Should we use background tasks?
- For trivial follow-up work, they are convenient. For anything that matters they are the wrong tool — they run in the same process with no retry and no persistence, so a restart loses them silently. Real work belongs in a queue.
- Do you work with businesses across Cardiff?
- Yes. We are based in Leicester, United Kingdom and work with clients throughout Wales, including Cardiff and the surrounding Cardiff area. Most collaboration happens remotely, and we travel for kick-offs and key milestones.
- What kind of Cardiff businesses do you usually work with?
- Public sector and broadcast work is common, and bilingual provision is usually a requirement rather than an option. Beyond that we work across Media & Broadcasting, Financial Services, Public Sector, Higher Education and Sport.
- Do you cover the areas around Cardiff?
- Yes — we work throughout Wales, including Bristol, Swansea. Cardiff is an urban area of roughly 490,000+, and we take on work across the wider Cardiff region rather than the city boundary alone.
Talk to us about FastAPI Development in Cardiff
A 30-minute call with someone who would actually work on it. No sales script, no obligation.
- Projects typically launched within 4–8 weeks
- No long-term contracts required
- All team members UK-based
- Dedicated account manager and development team
- Transparent reporting with monthly performance metrics
- Scalable from startup to enterprise