Financial software development

Financial software development is the engineering behind a fintech platform: the integrations, the apps, the SDKs, the orchestration logic and the back-office systems that keep the platform compliant and the books straight. Not every build needs all of it, but the parts have to fit each other.

We are a delivery partner for B2B fintech platforms in banking, payments, lending, KYC, open banking and BaaS. We work as one accountable squad inside your stack, own the architecture, and hand the work back documented, tested and ready to extend.

The unit of delivery is one working piece of software owned end to end, not a billable hour. That is the difference between adding capacity and adding accountability, and it is the gap most regulated platforms hit when a signed client is waiting on the path to production.

Recent builds shipped native Android payment SDKs, lending PWAs and the integration services behind them - see our cases.

Financial software development is regulated software development. We deliver to regulated buyers as a default, and we fit the buyer's oversight regime rather than the other way around.

What our delivery gives you by default:

• WislaCode Solutions PSA as the contracting EU entity, with IP and GDPR under EU jurisdiction.
• A documented sub-outsourcing chain in line with EBA outsourcing guidelines and DORA third-party risk rules.
• An outsourcing register entry, audit and exit clauses, and exit drill support where DORA applies.
• Delivery metrics tracked weekly: lead time, deployment frequency, change-fail rate, recovery time.
• Source code, tests, runbooks and documentation handed back, with code ownership that transfers cleanly.
• A replacement guarantee on every squad role, so a departure does not derail the build.

When one integration blocks revenue, the integration unblock sprint takes it live; when the next ten look alike, the reusable integration layer makes each cheaper than the last.

Fintech buyers compare us with three other kinds of partner: large system integrators that cost more and own less, local primes with less domain depth, and offshore staff augmentation that is cheapest but needs the most management.

We sit deliberately between them: EU-contracted, banking and product literate, with architecture ownership and a clean handover. You get the accountability of a prime without the price, and the depth of a specialist without renting a team you then have to run yourself.

It also means we say no to work that does not fit. If a scope is really staff augmentation, or it sits outside fintech and regulated delivery, we will tell you on the first call rather than stretch to take it. The engagements that work best are the ones where a signed client, a partner or a provider integration is waiting on the path to production, and a team that owns the architecture is what moves it.

Financial software is bought in different shapes depending on how settled the scope is, and we match the commercial model to that rather than forcing one. A defined build with a clear specification runs as fixed price against an acceptance test, so the cost and the milestones are known in advance.

An evolving platform, where the next quarter depends on what the last one taught you, runs as time and material with a named squad and weekly delivery metrics in your own tools. You see lead time, deployment frequency and change-fail rate as they move, not in a quarterly slide.

Where the value is a measurable result rather than a feature list, an outcome-based arrangement ties the terms to delivery in production. In every shape the EU contract, the IP assignment and the clean handover are the same, so the commercial model never changes who owns the code at the end.

Most financial platforms do not need a rewrite, they need the joins fixed and a few surfaces modernised. We extend what works through adapters and an orchestration layer, ship the new products and channels against that, and leave a full replacement as a separate decision made on its own timeline rather than under launch pressure.

That approach keeps the lights on while the platform moves forward. The legacy core keeps serving what it serves, the new work lands beside it behind a stable backbone, and the high-risk big-bang migration that sinks so many programmes never has to happen.

For the banking-core variant of this work, see legacy core banking systems integration.