$15K–$100K typical projects
Direct answer
FastAPI development engagements with me run $15K–$100K: a focused API service with auth and a clean data model sits near $15K–$30K, while a full production platform — background jobs, streaming AI endpoints, multi-tenant data, observability — lands in the $60K–$100K range. I bring 7+ years of production delivery, including guest engineering at Expensify, a platform serving millions of users, and I'm Top Rated on Upwork with $100K+ earned and verified reviews alongside direct clients worldwide. You get a backend built for the day after launch, not just the demo.
FastAPI is the best Python web framework for teams that need speed today and type-safe maintainability next year — but most FastAPI codebases in the wild are demo-quality: no migration discipline, blocking calls inside async routes, and zero observability. This service exists for companies that need the production version: an API that survives real traffic, real data, and the second engineer who joins the project.
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 product running on an aging PHP or early-Node backend hits its ceiling — slow endpoints, scary deploys, no types. I map the existing behavior, build FastAPI services alongside the old system, and migrate route by route behind a gateway so nothing breaks mid-flight. The outcome is a typed, tested, documented API and a decommissioned legacy server, without a big-bang rewrite risk.
A team has a working LLM prototype in a notebook and needs it to become a product. I build the FastAPI layer that production AI demands: streaming responses, request queuing, token and cost tracking, provider fallbacks, and rate limiting per customer. The result is an AI backend that stays up when a launch tweet sends a thousand concurrent users at it.
A startup shipping a React Native app needs the server side: authentication with refresh tokens, push notification delivery, media uploads, and an admin panel. Because I build mobile apps too, the API is designed around how mobile clients actually behave — flaky networks, retries, pagination, versioned endpoints — so the app team never fights the backend. Delivery includes OpenAPI docs the client is generated from.
The first week produces two artifacts: a data model reviewed with you before any endpoint exists, and a walking skeleton deployed to a real environment — one route, one database table, migrations, CI, and structured logging all wired. That skeleton is the most valuable week of the project, because every later feature rides on rails instead of being invented ad hoc.
From week two onward, delivery is vertical slices: each week ships complete features — schema, endpoint, tests, docs — deployed to staging where you or your app team can hit them immediately. Auth lands early because everything depends on it. Background jobs, webhooks, and third-party integrations come mid-project once the core resources are stable. The final two weeks are hardening: load testing the hot paths, tightening error responses, alerting, and a runbook so the first production incident is a checklist, not a panic.
Endpoint count matters less than people think — CRUD is cheap. What's expensive is state that changes over time: payment lifecycles with webhooks and reconciliation, subscription proration, order state machines, anything where two systems must agree about money. Second is concurrency: if your API must coordinate background workers, scheduled jobs, and real-time updates, the architecture work grows well beyond the routes.
Third is tenancy and access control — a single-tenant internal API is a fraction of the cost of a multi-tenant SaaS backend where every query must be scoped and audited. Fourth is integration surface: each external system (Stripe, Twilio, an EHR, a shipping provider) brings its own failure modes to handle gracefully. When I estimate, I break these out explicitly so you can see which requirement is buying which chunk of the budget, and cut deliberately rather than blindly.
If your product is admin-heavy — internal tools, content management, back-office workflows — Django's built-in admin will save you a month of dashboard building, and I'll say so in the first call. If your team is entirely TypeScript and will maintain this after I leave, a Node or NestJS backend they can actually own may beat a technically superior Python one they can't. And if you need a handful of simple endpoints in front of a database, a backend-as-a-service like Supabase gets you there for a tenth of the cost.
FastAPI earns its keep when you have real business logic in Python's wheelhouse: AI and LLM integration, data-heavy processing, complex validation, or high-concurrency IO. Choosing the framework after understanding the product — not before — is the difference between an engineer and an evangelist. A vendor who recommends the same stack for every problem is selling their comfort zone, not your outcome.
Ask three questions. First: 'How do you handle database migrations?' — anyone who hesitates or says they edit tables manually has never maintained a production API through schema changes; the answer should involve Alembic and reversibility. Second: 'What happens in your API when a downstream service is slow?' — you're listening for timeouts, retries with backoff, and circuit-breaking, because naive async code amplifies downstream failures instead of containing them. Third: 'Show me the OpenAPI docs of something you've built' — FastAPI generates these nearly for free, so their absence signals a prototype-quality operator.
Beyond technical answers, verify production history through channels that can't be faked: marketplace review trails, public products, referenceable clients. My own verification includes Top Rated status on Upwork with $100K+ earned and guest engineering at Expensify — whoever you hire, demand the equivalent.
Every engagement ships with the things that separate a real backend from a demo: reversible database migrations from commit one, test coverage on business logic and every auth boundary, structured JSON logging with request IDs so you can trace a user's error through the system, and error tracking wired to alerts before launch — not after the first outage.
You also get deployment as code — Docker plus CI/CD to your infrastructure of choice — auto-generated interactive API documentation your frontend team works from, and a handover session recorded for whoever inherits the codebase. I write READMEs that answer the question every future engineer asks first: how do I run this locally in under ten minutes? The measure of good delivery isn't the demo day; it's whether the next developer curses my name six months later. My goal is that they don't, and that's a checkable claim — ask my past clients' engineers.
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.
My engagements run $15K–$100K. A single-purpose API service — auth, a clean data model, a dozen endpoints, deployed with CI — lands around $15K–$30K. Mid-range ($30K–$60K) adds background jobs, payments, and integrations. The top of the range covers multi-tenant SaaS backends or AI platforms with streaming, queuing, and per-customer rate limiting. Hourly consulting on existing FastAPI codebases is also available for smaller problems.
Yes — FastAPI runs production workloads at large tech companies and thousands of startups, and its async model handles high-concurrency IO extremely well. The framework is not the risk; the implementation is. Production failures I see come from blocking calls inside async routes, missing migration discipline, and no observability — engineering practices, not framework flaws. A properly built FastAPI service will outlive most of the products built on it.
Yes, and it starts with a paid audit rather than a blind quote: I read the code, run it, and deliver a written assessment of what's solid, what's fragile, and what it will cost to get where you want. That protects both of us — you get an honest map before committing to a bigger engagement, and neither of us discovers surprises in month two.
Projects typically fall in the $15K–$100K 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