Fintech Software Development
Financial products fail on correctness and trust long before they fail on features. We build the transaction paths, the reconciliation, and the audit trail underneath them.
What is Fintech software development?
Fintech software development builds systems that move, store, or analyse money, where correctness and auditability matter more than feature velocity. It requires precise handling of monetary values, idempotent transaction processing, and a complete audit trail. Techroniqs has delivered BankBarn, a digital banking platform with secure authentication, account management and transaction processing, and Mosaic, an enterprise API aggregating cryptocurrency market data from more than 50 exchanges for financial institutions.
Key takeaways
- Never represent money as a floating-point number. Use integer minor units or a decimal type — this is the most common and most damaging bug in financial software.
- Every write that touches money must be idempotent, because networks retry and users double-click.
- An append-only audit trail is a design requirement from the first table, not a reporting feature added later.
- Authentication and session handling carry more risk here than anywhere else; we use established providers such as Clerk rather than building our own.
- High-frequency market data is a caching and indexing problem, which is what Mosaic solved with PostgreSQL and Redis.
What makes Fintech difficult
The recurring engineering problems in this sector, and how we handle each one.
- Transaction correctness under retries
- Idempotency keys on every money-moving endpoint, so a repeated request cannot double-charge.
- Reconciliation between systems
- A single ledger as the source of truth, with external systems reconciled against it rather than trusted individually.
- Data volume from market feeds
- Redis caching in front of PostgreSQL, with schema and indexes designed for the read patterns — the Mosaic approach across 50+ exchanges.
- Onboarding friction versus security
- Established auth providers and progressive verification, so security requirements do not push drop-off through the roof.
What we build in this sector
- Digital banking interfaces — accounts, transactions, and financial insight dashboards
- Payment integration and subscription billing via Stripe
- Market-data APIs and aggregation infrastructure
- Secure authentication and onboarding flows
- Financial reporting and analytics interfaces
Technologies we use in Fintech
- Next.js
- React
- Ruby on Rails
- Node.js
- PostgreSQL
- Redis
- Clerk
- Stripe
- RTK Query
- Vercel
Fintech work we have delivered
BankBarn
USFrontend Development
Digital banking platform with secure authentication, account management, transaction processing, and financial insights.
Read the case studyMosaic
GlobalBackend/API Engineering
Enterprise-grade API platform aggregating cryptocurrency market data from 50+ exchanges for financial institutions.
Read the case studyFrequently asked questions
What is different about building fintech software?
The tolerance for error is far lower and the audit requirements are far higher. A bug in a marketing site costs a visitor; a bug in a transaction path costs money and trust, and may need to be explained to a regulator. That changes how the data model, the retry behaviour, and the logging are designed from the first day.
How do you handle money in the database?
As integer minor units — cents rather than dollars — or a fixed-precision decimal type. Floating-point numbers cannot represent common decimal values exactly, so arithmetic on them accumulates error. This single choice prevents an entire category of financial bug.
Do you build your own authentication for financial products?
No. We use established providers such as Clerk or OAuth. Custom authentication is a large, permanent security liability with no product differentiation, and the risk is highest in exactly this sector.
Can you work with financial data at scale?
Yes. Mosaic aggregates cryptocurrency market data from more than 50 exchanges for financial institutions, with real-time exchange crawling, Redis caching, and PostgreSQL tuned for analytics read patterns.
Are you regulated or licensed to handle funds?
No, and that is deliberate. We build the software; funds move through licensed providers such as Stripe. Licensing, money transmission, and regulatory approval are your responsibility with your own compliance advisers, and we build to fit whatever that framework requires.
Related
Building something in fintech?
Tell us what you are working on. You will speak to an engineer who has shipped in this sector, and get a straight answer on fit.