Fintech App Development

Fintech apps where every cent is traceable, every flow is idempotent and auditors stop calling, built on a double-entry ledger you actually own.

What Fintech App Delivers

• A Double-Entry Ledger as the Single Source of Truth: Fintech is the category where shortcuts go to die. A naive payment record gets you to the first 100 users; the first regulator inspection or the first refund chargeback exposes everything that was hand-waved. We design for the audit on day one (double-entry ledger as source of truth, idempotency keys on every state-changing call, immutable event log), even when the MVP is small.
• KYC/AML Flows Designed for Real Conversion: Onfido / Veriff / Sumsub integration with progressive disclosure: we don't ask for everything upfront, only what the user's risk tier requires. Drop-off down 30-50% versus generic providers.
• BaaS Integration That Survives Provider Changes: A clean adapter layer above Solaris, Treezor, Modulr, Mangopay or Stripe Treasury so your business logic never depends on a single provider. Switching is a 6-week sprint, not a rewrite.
• Idempotent, Replayable Payments: Every state-changing call has an idempotency key. Network retries, BaaS outages and duplicate webhooks cannot create double charges or double credits, properties verified by integration tests.
• Regulatory Reporting Already Wired: SEPA INST, PSD2 SCA flows, Modelo 720/721 (Spain) for residency, transaction reporting for the Banco de España or local regulators. Built once, updated as regulation evolves.
• Fraud + Risk That Learns From Your Data: Rules engine plus optional ML scoring on velocity, device, geography. Reviewable rules in Git, monitored false-positive rates, manual review queue with full context for the analyst.

How We Build Your Fintech App

1. Regulatory & License Discovery: We map what your product actually does to the right regulatory framing (agent of an EMI, payment institution, money-remittance) so the build never collides with the compliance reality.
2. Ledger Design: Account chart, transaction types, fee accounting, FX handling. The ledger schema is the single most important decision; we get it right before writing UI.
3. BaaS + KYC Integration: Adapter layer with the chosen provider, full webhook coverage, retry/idempotency tested via simulated outages, KYC vendor with progressive UX.
4. Money-Movement MVP: One core flow live (top-up, transfer, card spend) with full audit and reconciliation. Closed beta with internal employees moving real cents.
5. Pen-Test + Pre-Audit: External penetration test, OWASP ASVS coverage, and a friendly pre-audit before the regulator meets us. We close findings before launch.
6. Public Launch + Watchful Eye: We sit with your team during the first month: fraud patterns and partner-outage modes only show up at real volume.

High-performance stack used by global leaders

React/Next.js/Angular on the frontend and Java 21 + Spring Boot + PostgreSQL 14 on the backend: the same stack that BBVA, ING, and Netflix use for their security and performance.

Fintech App: FAQ

Do we need a banking license to launch?

Most fintech MVPs ship under a BaaS partner's license as their agent. Getting your own EMI or PSP license takes 12-24 months and €500K-€2M, usually not the right first step. We help you decide the path with regulatory counsel.

How much does it cost?

A focused fintech MVP (one core flow, KYC, single BaaS provider) is €120,000-€220,000. Multi-flow neobank-style apps with cards, FX and lending reach €350,000-€800,000+.

How long to launch?

12-20 weeks to first audited transaction with one core flow. Full neobank-style products in 8-14 months.

Which BaaS partners have you integrated?

Solaris, Treezor, Modulr, Mangopay, Stripe Treasury and a couple of regional providers in Spain and LATAM. Our adapter layer means switching is contained, not catastrophic.

How do you handle PSD2 SCA?

Two-factor on every authentication and high-value transaction with biometric + device-bound key. We follow the EBA RTS and re-validate with each major version.

Can it handle FX and multi-currency?

Yes. Wise, Currencycloud or BaaS-native FX, with the ledger keeping each currency in its own accounts and FX rate snapshots stored per transaction for audit.

What about cards?

Virtual and physical cards via your BaaS partner or directly with Marqeta. Card issuance, controls (per-merchant blocks, daily limits, freeze/unfreeze) and 3DS, all in our toolkit.

Do you work with clients globally?

Yes. We work fully remote with clients across Spain, Europe, the US and LATAM. Time zones, video calls and live demos at every milestone.