Fintech App Development Company
Most fintech app development companies will sell you a 12-month roadmap before they ask what you actually need to launch. We do it the other way around. Revex is a fintech app development company that ships production-grade financial products — payment flows, dashboards, KYC-ready onboarding — in weeks, with the compliance-aware UX and integration depth that fintech actually requires.
We work with founders, operators, and engineering leaders who need a partner who already knows the rails: Stripe, Supabase, Plaid, webhook idempotency, RLS policies, audit logging. Not a generic agency learning on your money.
If you are evaluating a fintech development company and you want to skip the slide deck, the rest of this page is the short version of how we work.
What we build
Fintech is a category, not a product. The work splits into a few shapes that we ship over and over again. Most fintech apps we build combine two or three of these.
Payment flows
Checkout, subscriptions, marketplace payouts, invoicing, ACH transfers, refunds, disputes. The visible part is one screen. The work is webhook handling, retry logic, idempotency keys, reconciliation between your ledger and Stripe’s, and the edge cases that only show up after the first chargeback. We treat payments as a state machine, not a button.
Financial dashboards
Account balances, transaction history, statements, exports, internal admin views, finance team back-office tools. The interesting design problem is hierarchy: surfacing the one number that matters without burying the supporting detail. The interesting engineering problem is query performance once the ledger grows past a few hundred thousand rows.
Compliance-aware UX
Onboarding flows that collect KYC and KYB data without feeling like a form from 2009. Disclosures that meet regulatory requirements and still read like a sentence. Permission models that let a customer self-serve without exposing data they should not see. This is where most fintech apps feel cheap, and it is one of the highest-leverage places to spend design time.
Security posture
Fintech is a security-first category. Here is what that means in practice on our builds:
- Encryption everywhere. TLS in transit, encryption at rest, secrets in a managed vault — never in the repo or environment files committed to git.
- Row-level security by default. Supabase RLS policies written per table, tested as part of CI. A user can only ever query rows they own. We assume the client is hostile.
- Audit logging. Every state change on a financial record gets a row in an append-only audit table with actor, timestamp, before, after. This is non-negotiable for regulators and for your own debugging six months from now.
- Webhook idempotency. Stripe will deliver the same event twice. We assume that and dedupe on event ID at the database layer, not in app code.
- Least-privilege keys. Restricted API keys per environment, rotated on a schedule. No production secrets on engineer laptops.
- PCI scope minimization. Card data never touches our backend. Stripe Elements and Stripe.js keep us out of PCI scope wherever possible.
We are not a SOC 2 auditor and we will not pretend to be one. We will build the codebase and the operational hygiene that makes the audit go smoothly when you are ready for it.
Integrations we know cold
A fintech app is mostly the seams between systems. Pick the wrong primitives and the second feature takes three times as long as the first. We default to a stack we trust:
- Stripe — Payments, Connect for marketplaces and platforms, Billing for subscriptions, Issuing for card programs, Identity for verification, Tax for sales tax handling. We have shipped Stripe in every flavor.
- Supabase — Postgres as the system of record, RLS for authorization, Edge Functions for Stripe webhook handlers, Realtime for live balance and transaction updates, Storage for statements and KYC documents.
- Plaid — Bank account linking, balance and transaction history, identity verification, income and asset reports.
- Resend / Postmark — Transactional email for receipts, statements, and disputes.
- Vercel / Railway — Hosting that gives you predictable behavior and observability without a platform team.
We can work in your existing stack. We will be louder about it if we think a choice is going to bite you later.
How we work
Our process is built around a simple rule: every week, the product gets closer to something a real user can touch.
- Week 0 — Scoping. We turn your ticket list into a build plan with the smallest shippable surface area. We name what we are cutting and why.
- Weeks 1-4 — MVP build. Daily progress, weekly demos, code in your GitHub from day one. If you need a faster path, see our 4-week MVP program.
- Weeks 5+ — Iterate. We ship to a small group of real users and respond to what they actually do, not what they say in interviews.
- Handoff or stay. You can take the codebase in-house with a full walkthrough, or we stay on as your engineering team. Your call.
For broader product work outside fintech, our SaaS development page covers how we build B2B software more generally.
Frequently asked questions
How is Revex different from a typical fintech app development company?
Most fintech development companies sell hours. We sell shipped product. Our engagements are scoped to outcomes — a working payment flow, an onboarding that passes KYC, a dashboard your finance team uses every day — not a quarterly retainer.
Do you handle compliance directly?
No. We build the product in a way that makes your compliance program easier — audit logs, RLS, encrypted storage, documented data flows — but we do not file paperwork with regulators. You will want a compliance lead, a money transmitter attorney, or a SOC 2 auditor depending on your regulatory exposure. We work alongside them.
Can you work with our existing codebase?
Yes. About a third of our work is taking over a stalled or messy fintech codebase and getting it back to a shippable state. We start with a one-week diagnostic so we are not guessing.
What does a fintech build cost?
Most fintech MVPs land between a focused four-week sprint and a three-month engagement, depending on integration count and compliance surface. We will give you a fixed-scope quote after a scoping call. No open-ended hourly contracts.
Do you work with regulated entities, like broker-dealers or money transmitters?
We have shipped work for products operating under a licensed partner, BaaS arrangement, or sponsor bank. We have not directly built a broker-dealer from scratch and would not pretend otherwise. If your structure is novel, the scoping call is where we figure out fit.
What stack do you recommend for a new fintech app?
Next.js or React Native on the front end, Supabase or Postgres for the system of record, Stripe for payment rails, Plaid for bank linking, hosted on Vercel or Railway. This stack gets you to production fast without painting yourself into a corner.
Book a call
If you are scoping a fintech build and want a direct conversation with the people who will actually write the code, book a call. Thirty minutes, no slide deck, you leave with a clear sense of scope and timeline.