FastAPI developers build Python-based APIs and backend services that support web applications, microservices, data products, and AI-driven workflows. They can help you turn backend requirements into validated endpoints, clear API documentation, secure authentication flows, and scalable services that frontend, product, and data teams can use with confidence. If your project also involves frontend interfaces, you may want to explore hiring full stack developers for end-to-end support.
What does a FastAPI developer do?
A FastAPI developer designs and implements Python APIs and backend systems using FastAPI, a modern web framework built around Python type hints, validation, and automatic API documentation. This includes architecting RESTful endpoints with proper request and response validation, connecting databases using ORMs (Object-Relational Mapping) such as SQLAlchemy or SQLModel, implementing authentication and authorization flows, structuring asynchronous operations for performance-sensitive workflows, writing automated tests, containerizing services with Docker, and deploying to cloud platforms.
Common deliverables include API route implementations with Pydantic schemas for validation, database models and migration scripts, authentication middleware and security configurations, automated test suites, interactive API documentation (OpenAPI/Swagger), Docker configurations, deployment pipelines, and handoff documentation. Depending on project scope, a FastAPI developer may collaborate with frontend developers who consume the API, DevOps engineers who manage deployment and monitoring, data teams who provide schemas and integrations, or product managers who define feature requirements and success metrics.
How to hire a FastAPI developer on Upwork
Hiring a FastAPI developer on Upwork starts with a clear scope, then moves through candidate evaluation, interviews, and a written agreement on deliverables. A structured process helps candidates estimate accurately and helps you compare proposals based on the same requirements.
Step 1: Post a job
Start by defining the API deliverable, your tech stack, timeline, and acceptance criteria so qualified candidates can assess fit and propose accurately. A strong FastAPI job post includes:
- API goal and backend deliverable, such as a new service, endpoint expansion, integration, migration, or debugging project
- Tech stack details, including Python version, FastAPI, Pydantic, database, cloud provider, and CI/CD tools
- Required integrations, such as third-party APIs, frontend frameworks, authentication services, or data pipelines
- Timeline, milestones, and deployment target
- Budget preference, including hourly or fixed-price structure
- Acceptance criteria, such as tests, documentation, response-time goals, and security expectations
After you outline the scope, use the Job Post Generator, powered by Umaโข, Upwork's Mindful AI, to create a customizable starting point. Describe your project in a few sentences, then refine the draft with stack details, deliverables, and success metrics. You can also review this job description template for guidance on structuring responsibilities and requirements.
Step 2: Evaluate candidates
Review proposals and shortlist candidates based on relevant FastAPI and Python backend experience. Focus on:
- Portfolio examples showing FastAPI APIs, RESTful services, or microservices work
- Evidence of database integration, authentication, async workflows, testing, and deployment
- Client reviews that mention communication, documentation quality, debugging skill, and reliability
- Proposal quality, including whether the freelancer identifies architecture decisions, validation steps, potential risks, and timeline estimates
- Certifications or specializations, such as AWS, Docker, PostgreSQL, or Redis, if relevant to your stack
- Job Success Score (JSS) and talent badges such as Top Rated or Expert-Vetted
Use Upwork's shortlist and comparison features to organize candidates before scheduling interviews. For developer-specific evaluation guidance, see how to evaluate developer skills.
Step 3: Interview your top choices
Interview your top candidates with a structured 30-minute discussion that validates technical judgment, problem-solving approach, and communication fit. During the interview:
- Ask the candidate to walk through a FastAPI service they built, including how they structured routes, schemas, dependencies, and tests
- Discuss how they decide when to use async routes, background tasks, queues, or separate microservices
- Explore their approach to securing APIs that handle user data or payment workflows
- Confirm what information they need from you to estimate timeline and cost accurately
- Clarify communication preferences, update frequency, and how they handle scope changes or unexpected issues
Use Instant Interviews to collect structured video responses early, then move strong candidates to a live conversation. Upwork's built-in messaging and video tools let you schedule, conduct, and document interviews in one secure workspace.
Step 4: Agree on scope and begin work
Before the contract starts, finalize deliverables, milestones, communication expectations, and payment terms so both parties have clear alignment. Use Upwork's contract workroom to keep scope, approvals, and change requests documented in one place, and use funded milestones for fixed-price work so payments are held as project funds and released when you approve deliverables.
Before work begins:
- List final deliverables, including endpoint list, schemas, database models, auth flows, tests, and documentation
- Set milestones for fixed-price projects, such as architecture review, implementation, QA, and deployment
- Define success criteria, including test coverage thresholds, API documentation completeness, and deployment validation
- Confirm revision process, including how approved changes will be added to scope
- Agree on communication cadence, such as daily standups, weekly progress updates, or async messaging check-ins
- Document how access, credentials, and files will be shared securely after the contract starts
Upwork is not affiliated with and does not sponsor or endorse any of the tools or services discussed in this article. These tools and services are provided only as potential options, and each reader and company should take the time needed to adequately analyze and determine the tools or services that would best fit their specific needs and situation.
The rates and information provided in this article are based on current data and industry sources available at the time of publication. Freelance rates can vary depending on factors such as experience, location, project scope, and market conditions. Readers are encouraged to conduct their own research to confirm current rates and trends, as this information may change over time.