Fintech products live or die on trust. Your web application has to earn it in the first 5 seconds.
Fintech web applications carry a compliance burden that other verticals don't. PCI DSS for payments, FINRA record-keeping if you touch investments, SOC 2 readiness if you want enterprise customers. We build fintech web applications that work correctly and hold up under scrutiny. Fixed scope, fixed price.
You're building a fintech product and need a web application that handles financial data with the security posture, audit trails, and compliance architecture that regulators and enterprise customers require.
Fintech web applications fail in ways that non-fintech applications don't: a financial calculation error isn't a UX problem, it's a legal liability; a data breach in a fintech product exposes account numbers and transaction histories, not just email addresses; and a compliance gap discovered during a regulatory review can shut down the business, not just cost a fine. The development decisions that create these problems are made early — the database schema design, the authentication model, the audit logging architecture — and they're expensive to retrofit after launch.
The specific compliance considerations by fintech category: payment products need PCI DSS scoping to be handled correctly (Stripe's Stripe.js and payment elements keep card data off your server, but the implementation needs to be correct or PCI scope expands back to you); lending products need state licensing compliance infrastructure and the ability to demonstrate fair lending practices with audit trails; investment products face FINRA and SEC record-keeping requirements; and any product that aggregates bank accounts via Plaid or similar needs to handle the OAuth token management correctly and store refresh tokens with appropriate encryption.
The architecture decisions that matter: data encryption at rest (not optional for financial data), server-side calculation for anything money-related (client-side financial calculations create manipulation vectors), immutable transaction ledgers (financial events should append, not update), and the audit trail that shows exactly what happened to every dollar.
A production fintech web application with secure authentication, encrypted data storage, audit logging, Stripe or Plaid integration, and the architecture that passes compliance review.
Stripe integration for payment products
Stripe.js and Payment Elements for PCI-compliant payment collection. Stripe Connect for marketplace money movement. Stripe Treasury for embedded financial accounts. Webhook handling with idempotency keys for reliable payment event processing.
Plaid integration for data aggregation
Plaid Link for bank account connection. Token management with encrypted refresh token storage. Transaction sync with reconciliation logic. Balance and account data with appropriate caching to respect Plaid's rate limits.
Financial data architecture
Immutable transaction ledger with append-only records. Double-entry accounting patterns where appropriate. Decimal math throughout (never floating point for currency). Audit trails on all financial operations.
Compliance-ready architecture
Role-based access control with granular permissions. Complete audit log of all data access and financial operations. Data retention policies configurable per regulatory requirement. Export functionality for regulatory reporting.
Security baseline
TypeScript strict mode throughout. Parameterised database queries. CSP headers. Rate limiting on all financial operation endpoints. Session management with appropriate timeout for financial applications.
One honest number to start.
Fixed-scope, fixed-price. The number below is the starting point — final scope is built from your brief.
A production fintech web application with secure authentication, encrypted data storage, audit logging, Stripe or Plaid integration, and the architecture that passes compliance review.
Three steps, every time.
The same repeatable engagement on every project. No surprises, no mystery, no billable ambiguity.
Brief & discovery.
We send you questions, then get on a call. Output: a written scope with every step, feature, and integration listed.
Build & ship.
Fixed schedule, weekly reviews. No scope creep unless you change the scope — and if you do, we reprice it transparently.
Warranty & retainer.
30-day warranty on every launch. Most clients stay on a monthly retainer for ongoing features and maintenance.
Why Fixed-Price Matters Here
Fintech founders raising from investors or applying for money transmission licenses need predictable development costs. Fixed scope, fixed price.
Related engagements.
Stripe's documentation is excellent. Stripe's edge cases are not documented.
Read more02HIPAA compliance is not a checkbox. It's an architectural requirement that must be built in from the start.
Read more03You have the SaaS idea. We build the production MVP while you close your first customers.
Read moreQuestions, answered.
SOC 2 Type I readiness is achievable from day one if the application is architected with the right logging, access controls, and change management processes. The application architecture supports SOC 2 requirements; the operational processes (incident response, access reviews, change management) are the founder's responsibility to document. PCI DSS compliance via Stripe's recommended implementation is standard. Specific certifications (SOC 2 Type II, ISO 27001) require ongoing operational commitment beyond the development engagement.
All financial calculations are performed server-side using integer arithmetic in the smallest currency unit (cents, not dollars). Floating-point arithmetic is never used for money. Results are validated against expected ranges before being committed to the database. All calculation inputs and outputs are logged.
Yes — building on embedded finance infrastructure providers (Unit, Column, Stripe Treasury) is a common pattern for fintech products that want to offer banking features without a bank charter. The integration with these providers is part of the project scope.
Fintech applications with payment integration and compliance architecture: $30k–$60k. Applications with embedded finance infrastructure integration: $50k–$85k. Fixed-price.
Tell Ryel about your project.
Describe what you’re building and what outcome you need. You’ll have a written, fixed-price scope within the week.