$20K–$90K typical projects
Direct answer
I design and build Firebase backends for React Native apps at $20K–$90K: the low end covers architecting the Firestore data model, security rules, and Cloud Functions for a new app, the high end covers rescuing and rebuilding a production backend under live traffic. I have 7+ years of production delivery, 20+ App Store launches, and Top Rated status on Upwork with $100K+ earned and verified client reviews. Most engagements start with a backend audit — data model, rules, functions, and billing — that produces a findings report before any rebuild decision.
In a Firebase app the backend is invisible until it fails — then it fails as security holes, thousand-dollar invoices, and screens that take four seconds to load. This service is for teams whose React Native front end is fine but whose Firestore model, security rules, and Cloud Functions need to be designed, fixed, or rescued by someone who has operated this stack in production.
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 team is starting a React Native app on Firebase and wants the foundation right. I design the Firestore collections around the app's actual screens, write and test the security rules, define where Cloud Functions are required versus client logic, and set up emulator-based local development with CI. The team builds features on rails instead of improvising a schema one screen at a time.
A live app has rules written under deadline pressure, and the founders honestly do not know what a hostile user could read or write. I audit the rules against every collection with adversarial tests — direct API access, not just app behavior — and deliver fixes with a regression suite. Typical findings include user data readable across accounts and writable fields that should be server-only.
An app that worked at a thousand users is struggling at fifty thousand — hot documents throttling writes, feeds that cost a fortune to render, functions timing out. I restructure the model with aggregation documents, sharded counters, and paginated queries, migrating collections live with dual-write bridges so the app never goes down. Latency and the monthly bill both drop measurably.
This is the backend half of the stack, offered on its own, because that is where Firebase projects actually go wrong. Plenty of teams have React Native covered — an in-house developer, an existing codebase, a front-end contractor they like — but nobody who has designed a Firestore schema past tutorial scale, written security rules they would bet the company on, or debugged a Cloud Function that fails one time in two hundred. I slot in as that person.
Concretely the surface includes: Firestore data modeling and migrations, security rules with automated tests, Cloud Functions in TypeScript for server-side logic, authentication flows including custom claims for roles, push notification pipelines, and billing forensics. The deliverable is not just working configuration — it is a documented backend your front-end developers can build against confidently, with local emulators and CI so backend changes are testable before they touch production.
For any existing app, I start with a fixed-scope audit, one to two weeks. I read the data model against the app's real query patterns, run adversarial tests against the security rules from outside the app, review every Cloud Function for retries, idempotency, and timeout behavior, and reconcile the billing console against what the usage should cost. The output is a written report: vulnerabilities ranked by severity, cost leaks quantified, structural risks explained in plain language, and a prioritized fix plan.
The audit is deliberately standalone. Some clients take the report and fix things in-house; some hand me the top of the list; a few discover their backend is actually fine and buy nothing further, which is a legitimate outcome I am happy to deliver. Starting with diagnosis also protects you from the consultant failure mode of prescribing a rebuild because rebuilds are what pays.
Greenfield architecture sits at the low end: model, rules, core functions, and development setup for a new app runs $20K–$35K, and it is the best money in this category because every decision is still cheap to make. Fixes to a live backend cost more than the same work would have cost upfront, for one reason: migration. Changing a Firestore schema under live traffic means dual-write periods, backfill jobs, and staged rollouts, all of which is careful, unglamorous engineering.
The multipliers that push toward $90K: data volume and traffic level during migration, how many collections need restructuring versus patching, multi-role permission systems that need rules rewritten from first principles, and function estates with dozens of undocumented endpoints to reverse-engineer. One factor that surprises clients: the absence of any staging environment. If production is the only Firebase project you have, building safe rails to work on is the first, unavoidable line item.
Ask how they test security rules. The only acceptable answer involves automated tests against the rules themselves — emulator-based suites simulating hostile requests — because clicking through the app proves nothing about what the API allows. Ask them to explain a Firestore bill: a candidate who cannot trace reads, writes, and listener behavior to invoice line items will not find your cost leak. Ask when they would put logic in a Cloud Function versus the client, and expect a nuanced answer about trust boundaries, latency, and offline behavior rather than a rule of thumb.
For migration work specifically, ask them to describe a live schema migration they have executed — the dual-write period, the backfill, the rollback plan. This is the highest-stakes work in the Firebase world and the easiest to claim falsely, because the difference between having done it and having read about it only surfaces mid-migration, which is the worst possible time.
If your app has no users yet and your backend pain is theoretical, do not buy a rescue — buy a few hours of architecture review to catch the worst decisions early, and spend the difference on reaching users. If your backend problems stem from a product that changes direction weekly, stabilize the product first; no schema survives a pivot a month, and you will pay migration costs repeatedly for nothing.
If the audit reveals your workload is fundamentally wrong for Firestore — analytical queries, heavy relational integrity, complex reporting — the honest recommendation is a different backend, and I will make it, including scoping what a migration off Firebase looks like rather than selling you years of workarounds. And if the actual problem is one slow screen, buy a focused fix, not an engagement. Matching the intervention to the size of the problem is most of what senior judgment is for.
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.
Greenfield backend architecture — Firestore data model, tested security rules, core Cloud Functions, and development setup — runs $20K–$35K. A security and cost audit of an existing backend is a fixed one-to-two-week engagement at the bottom of that range. Restructuring a production backend under live traffic runs $40K–$90K, with migration complexity, not code volume, driving the number.
You test them from outside the app: automated suites that hit the Firestore API directly, simulating a hostile authenticated user trying to read other accounts' data and write protected fields. If your rules have never been tested that way, assume they have holes — most audited apps do. Clicking through the app proves only what your UI attempts, not what your API permits.
Fix first, in most cases. The majority of Firebase pain — slow screens, high bills, throttled writes — traces to data model decisions that can be corrected in place for far less than a migration. Move off Firebase when the workload is genuinely mismatched: heavy relational logic, analytical reporting, or regulatory constraints on data residency. An audit distinguishes the two situations before you commit either budget.
Projects typically fall in the $20K–$90K 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