$20K–$120K typical projects
Direct answer
Hiring me as a FastAPI developer costs $20K–$120K per project: the low end covers a focused API service with authentication, tests, and deployment, while the high end covers a complete production backend with background workers, AI model serving, and the operational tooling to run it. I bring 7+ years of production delivery, I'm a Guest Engineer at Expensify, and I'm Top Rated on Upwork with $100K+ earned and verified client reviews. The hiring process is simple: one scoping call, a written milestone plan with fixed prices, and working endpoints in your staging environment within the first two weeks.
FastAPI is the default choice for modern Python backends — async, typed, fast, and the natural home for AI-powered APIs — but the framework doesn't make architectural decisions for you. I build FastAPI backends that hold up in production: clean dependency structure, real test coverage, honest async, and deployments your team can operate without me.
You need an MVP or v2 shipped on budget with someone who makes architecture decisions and owns delivery end-to-end.
You need a senior IC to augment the team, rescue a codebase, or lead mobile + AI integration without months of hiring.
You need a reliable senior subcontractor for client projects — clear communication, store-ready quality, white-label friendly.
30 minutes — goals, stack, timeline, budget range.
Fixed milestones, clear deliverables, start date.
Weekly demos, async Slack updates, production standards.
Store launch, documentation, knowledge transfer.
A startup validated demand on airtable-and-automation glue and now needs a real backend. I build a FastAPI service with proper data modeling, authentication, role-based permissions, and versioned endpoints their mobile and web clients share. They migrate off the no-code stack incrementally, feature by feature, and end up with an API they can hire ordinary Python engineers to extend.
A company has models and prompts that work in notebooks but no way to serve them to customers. I build the FastAPI layer around them: streaming responses, request queuing with backpressure, timeouts and fallbacks around model calls, usage metering per API key, and observability on latency and cost. Their data scientists keep iterating on models while the API contract stays stable.
A team's existing Python API buckles under slow upstream calls — threads exhausted, requests queuing, timeouts cascading. I port the hot paths to FastAPI with genuine async I/O, move heavy work to background workers, and leave the stable CRUD surface where it is. Throughput on the affected endpoints multiplies without a big-bang rewrite of the whole service.
Week one produces the skeleton that everything else hangs on: project structure, database models and migrations, authentication, CI with tests running on every commit, and a deployed staging environment. I front-load this because a FastAPI project's long-term quality is mostly decided by its first week — dependency injection discipline, settings management, and test layout are cheap to establish and brutal to retrofit.
From there, work ships in weekly vertical slices: each milestone is a set of endpoints you can call in staging, with tests and documentation generated from the type annotations, not a promise of future integration. You review working software every week, which keeps scope honest in both directions. A typical product backend takes six to twelve weeks; the last milestone is always operational handover — runbooks, alerting, and a walkthrough with whoever maintains it next.
The floor of the range buys a well-built single service: CRUD and business logic, auth, tests, docs, automated deploys. Three things push toward the ceiling. First, background processing — anything with queues, scheduled jobs, long-running tasks, or webhook fan-out roughly doubles the operational surface, because now there are workers to monitor, retries to design, and failure states to handle. Second, AI serving: streaming, model fallbacks, token metering, and cost controls are their own discipline beyond ordinary REST.
Third, integration count and data sensitivity. Every third-party system adds auth flows and failure modes; healthcare or fintech contexts add audit logging, access controls, and review cycles. What doesn't move price much is endpoint count — fifty endpoints on a clean architecture cost less than fifteen on a muddled one. If your scope sits at the low end, I'll say so rather than inflate it.
The most common failure I'm hired to clean up is fake async: handlers declared async that call blocking database drivers or requests-style HTTP clients inside them, silently serializing the event loop. Ask any candidate how they'd verify an endpoint is actually non-blocking; if the answer doesn't involve knowing which libraries block, keep interviewing.
Second red flag: no story on testing. FastAPI makes testing unusually easy — dependency overrides, a built-in test client — so a candidate without meaningful coverage on past projects chose not to test, which tells you everything. Third: treating the auto-generated docs as the whole documentation story while leaving deployment, migrations, and environment setup in their head. Fourth: reaching for microservices immediately. A senior FastAPI developer ships you one well-structured service and splits it only when something measurable forces the issue — premature service boundaries are the most expensive mistake in this stack.
When the engagement ends you should have: a repository your own engineers can navigate without me, tests that fail when behavior changes, migrations that run in CI, one-command deploys to staging and production, and monitoring that pages someone before customers notice. The interactive API documentation should be accurate because it's generated from the code, and a new engineer should get from clone to running locally in under fifteen minutes following the README.
Just as important is what you shouldn't have: no snowflake environments that only work on my machine, no secrets in the repo, no endpoints that exist but aren't tested, and no architectural decisions that live only in my head. I write short decision records for the choices that will confuse someone in a year — why this queue, why this auth pattern — because a backend's maintenance cost is mostly determined by how explainable it is.
If your team is already productive in Django and your product is CRUD-plus-admin, Django's batteries — admin panel, auth, ORM conventions — will likely ship faster than a bespoke FastAPI build, and hiring for framework novelty is buying a rewrite nobody asked for. FastAPI earns its place when you need async throughput, typed API contracts, or an AI/ML serving layer, not as a fashion statement.
You also shouldn't hire anyone to build a backend you can avoid entirely. If your app's needs are auth, a database, and file storage, a backend-as-a-service platform gets you to market in days, and a custom API becomes worthwhile only once business logic outgrows it — I'll tell you when you're there. And if the actual bottleneck is one slow query or a missing cache, that's a one-week fix, not a $20K project; I've turned that engagement down before and will again.
You approve milestones and a price before any build starts — no open-ended hourly surprises.
You see running software each week, not status reports, so you can course-correct early.
The person who scopes the work is the person who builds it — no junior layers, no agency markup.
Top Rated on Upwork with public client reviews and $100K+ earned, plus contributions to Expensify. Check the receipts before you commit.
Chat-Based Financial Collaboration
Contributed 50+ merged pull requests to New Expensify — the production React Native app used by millions for chat-based expense management — working through Expensify's fully public open-source process alongside their core engineers, and recognized with a Guest Engineer invitation to their Curaçao offsite.
Food Truck Discovery Platform
Production food-truck discovery platform for US cities — customer and vendor React Native apps on iOS and Android, plus customer and vendor web, with AI features. Helps people find trucks nearby while vendors manage schedules, orders, and events.
Rewards & Engagement Platform
End-to-end React Native app for the US market with gamified rewards, real-time engagement, and secure payment flows — built from product scoping to App Store launch.
Freelance FastAPI development for a complete production backend typically costs $20K–$120K depending on scope: a focused API service with auth, tests, and deploys sits near the low end, while backends with background workers, AI model serving, and heavy integrations reach the high end. Hourly senior rates in this specialty generally run $80–$150; I prefer fixed-price milestones so the risk sits with me, not your budget.
A production backend for a typical SaaS or mobile product takes six to twelve weeks: a foundation week for structure, auth, CI, and staging deploys, then weekly milestones of working endpoints. Smaller scopes — a serving layer for an existing model, a webhook processing service — often ship in three to four weeks. You're calling real endpoints in a staging environment by the end of week two.
Choose FastAPI when your product is API-first — mobile or SPA clients, third-party consumers, or an AI serving layer — and benefits from async I/O and typed contracts. Choose Django when you need lots of conventional web features fast: admin interface, sessions, forms, and a mature plug-in ecosystem. Both are production-proven Python; the wrong choice is picking either for fashion rather than for the shape of your workload.
Projects typically fall in the $20K–$120K range depending on scope, integrations, and timeline. I provide a fixed-scope proposal after a 30-minute scoping call.
MVPs often ship in 8–12 weeks. Production systems with AI backends or RAG may run 12–20 weeks. Rescue and audit engagements can start within days.
Yes. I work with founders, CTOs, product teams, and agencies worldwide — US, UK, EU, and APAC time zones with async updates and weekly demos.
Yes. I specialize in React Native + Python (FastAPI) + AI (RAG, agents, OpenAI/Claude) under one senior owner — fewer handoffs, faster shipping.
Book a free 30-minute scoping call on this site, hire through Upwork, or email dhairyasenjaliya@gmail.com with your brief and timeline.
30-minute scoping call · Clear milestones · Senior engineer ownership