Prostrive builds custom banking software for banks, building societies, credit unions and licensed FinTech firms that need products their current platform can't deliver. We design the digital channels, integrations, payment and compliance systems around your core, and modernise that core in stages when it holds you back. Our engineers join your team, and the code is yours.
Let's talkMost banks come to us when their platform or vendor becomes the reason a change can't happen: a product the roadmap needs, a channel customers expect, a scheme or regulatory deadline, or a backlog their in-house team can't clear.
That work almost always happens around a core banking system that can't simply be switched off. That's why we don't just supply developers. Our teams know how live ledgers, payment flows and audit requirements behave when something new is connected to them.
The services below cover the full stack, from the screens your customers use to the systems that move money, lend it and check where it came from. Each of these systems is only as reliable as its connection to your ledger, which is why we put the integration with your core and existing systems in scope from day one, not at the end.
Online banking portals and web platforms where customers check balances, move money and manage cards. The interface is rarely the hard part; keeping balances and transaction states consistent in real time across every channel is. We saw that on Axys, a card platform for high-net-worth clients, where users manage their cards, track transactions and access rewards.
Native and cross-platform banking apps for iOS and Android, built with React Native or Flutter. Biometric login, card freezes, instant notifications and payments run on the same backend and APIs as your web channel, so a customer sees the same balance wherever they log in.
An integration layer between your core banking system and everything built on top of it. New products read and write through well-defined APIs, so the ledger stays the single source of truth. We did similar API work for Globus Payments, connecting an EMI-licensed payment company to banks and financial service providers.
Account information and payment initiation services under PSD2 and the UK open banking standard. That means secure API access for authorised third parties, consent journeys customers understand, and strong customer authentication that satisfies the rules without adding friction to every login.
Payment flows over Faster Payments, Bacs, CHAPS and SEPA, including ISO 20022 messaging and the reconciliation that proves every transaction landed where it should. In payment processing speed matters, but in our experience traceability matters more: each payment has to be matched, reported and recoverable when something fails halfway.
We can build loan origination, underwriting decisions, servicing, repayment schedules and collections in one flow. Lending software encodes your credit policy, so we design it to change as quickly as that policy and the rules around it, without rewriting the parts that already work.
KYC onboarding, AML transaction monitoring, sanctions screening and fraud detection, built into your processes. Machine learning models flag unusual patterns in real time, while rules and audit trails keep every decision explainable to your compliance team and to the regulator.
Reporting and analytics that bring product, risk, operations and compliance data together, so every team works from the same numbers. Where it pays off, our AI developers add models on top, such as credit scoring that can also assess customers with a thin credit file.
A CRM that joins customer interactions to the records in your core, so relationship managers and support staff see one customer instead of five systems. Consent and data protection rules sit in the data model of the banking CRM, not in a setting someone has to remember.
ATM and self-service applications, including transaction logic, remote monitoring and updates, and the integration with your core banking system. Encryption and anti-skimming controls protect every withdrawal, balance check and transfer made without a visit to a branch.
In most projects we advise banks to start at the digital or integration layer and treat the core as a separate decision. In our experience, the layer you change drives risk, cost and pace far more than the feature list, together with the state of your core and the number of integrations.
The digital layer holds your customer-facing web and mobile channels. Changes here are contained and easy to reverse, and because customers judge your bank on this layer, it's where we usually start new products, on top of the core you already run.
The integration layer exposes core functions through APIs to your channels, partners and open banking providers. This is where most of our banking work pays off: once the layer exists, new products stop needing changes deep inside the core.
The core banking layer holds the ledger, accounts and transaction records every other system depends on. We treat changes here as a programme with its own risk plan, never as a side task, because one mistake reaches every customer.
Few banks should write a new ledger from scratch. When we modernise a legacy core, it's through one of three routes: buying a modern core, migrating in phases or wrapping the old one. In each, our work sits in integration and data migration. We don't sell a core platform ourselves, so we have no reason to push one.
Buy a modern core from platforms such as Temenos, Mambu or Thought Machine, and build what sets you apart around it. If an off-the-shelf core or a Banking-as-a-Service provider covers your need, we'll tell you buying is the better route, and take on the integration, data migration and products on top.
Products or customer groups move off the legacy core one step at a time, with old and new running in parallel. Each phase carries less risk than a big-bang switch, at the price of a longer programme and the effort of keeping two systems reconciled.
Leave the core, often a COBOL mainframe, in place and expose its functions through an API layer. New digital products arrive fastest this way, but the limits of the old core remain, so we treat wrapping as a first step rather than the end state.
Compliance shapes banking software from the first design session: where data is stored, what gets logged, how payments are authenticated and how the system keeps running under stress. Added at the end, it means rebuilding. Your firm keeps the licence and stays accountable to the regulator; our job is banking software that makes meeting those obligations straightforward and easy to evidence.
Card data falls under PCI DSS and personal data under UK GDPR and the EU GDPR, which decide where customer data may live and who may see it. We design encryption, access control and audit trails into the architecture, so an auditor's question is answered by the system rather than by a spreadsheet.
PSD2 requires strong customer authentication and secure access for authorised third parties, and the move to ISO 20022 changes the data every payment carries. That's why we settle login, payment and API flows against these rules before any screen is drawn.
FCA and PRA rules on operational resilience expect banks to keep important business services within impact tolerances and to control outsourcing and third-party risk. In the EU, DORA sets similar demands on banks and their ICT providers, and that includes us as your development partner. We shape how we work around your resilience and exit arrangements.
A banking software development company should be judged on how it works inside a regulated bank, not on a gallery of apps. These are the five checks we'd use ourselves, with how Prostrive answers each one. Put them to anyone you shortlist, including us.
Ask what a partner has connected to, not only what they have built. Integrating with a live ledger, payment scheme or card processor is a skill of its own. Ours includes API integrations with banks for Globus Payments, the Axys card platform and FiatGate, a white-label crypto exchange.
A good partner explains how PCI DSS, AML obligations and data residency change the design before you ask. If compliance first appears in testing, expect rework. That's why we map the regulatory context in discovery, alongside your systems and goals.
Change boards, security reviews and release windows exist for a reason. Our teams work inside them, with least-privilege access, every change traceable to a ticket and a review, and documentation your auditors can follow.
Lock-in usually starts in the contract. On our standard contracts you own the code and the intellectual property, and there are no long-term commitments, so you can scale the team up or down or bring the work in-house.
Remote engineers only work when they're part of your team. Ours join your standups and Slack channels, work under Western on-site management in our hubs and receive cultural and communication training, so questions surface early instead of in a rework ticket.
There are three ways to work with our banking software engineers, and you decide how much of the steering you keep. Many banks start with one model for a first product and switch as the programme grows. With no long-term contracts, that switch doesn't mean renegotiating a lock-in.
A Prostrive team that works under your own management, as an extension of your in-house engineers. It fits banks with a strong internal tech lead that want more capacity on the core, integrations or channels without adding permanent headcount.
Prostrive manages the team: our leads take care of planning and delivery while you set the priorities. This model fits a new digital channel or product where you want expert oversight without managing developers yourself.
A defined scope delivered end to end, from discovery to deployment. It suits a contained piece of work such as an open banking integration, a lending module or one phase of a core migration.
Banking projects usually derail on existing systems, integrations and regulatory context, so our four-step process deals with those first. Constraints surface in discovery rather than halfway through the build, and the build itself runs in reviewed increments.
A selection of the products our embedded teams have helped build.
Book a Discovery call about the change your bank needs to make. We'll look at your current systems and constraints together, and you'll leave knowing which layer to start in and which team setup fits your project.
Custom banking software development is the design, building and integration of software tailored to a bank's own products, processes and regulatory obligations, instead of adopting an off-the-shelf system unchanged. It covers customer channels such as online and mobile banking, the integration layer around the core, payment, lending and compliance systems, and the modernisation of legacy cores. At Prostrive, most of this work happens around a core the bank already runs.
A bank should build custom software when the product, customer experience or integration it needs is what sets it apart, and no platform supports it without heavy workarounds. For commodity functions such as the ledger itself, buying a proven core or using a Banking-as-a-Service provider is usually the better choice, and we'll say so. Most banks combine both: they buy the core and build the channels, integrations and products that differentiate them around it.
Yes. Building on top of an existing core banking system is the most common form of our banking work. We add an integration layer that exposes core functions through APIs, so new digital channels, open banking services and products can use the ledger without changes deep inside it. That keeps the core as the single source of truth and lets you modernise it later, as a separate decision.
No, a COBOL core doesn't have to be replaced before you can modernise. Many banks still run COBOL mainframes because they process transactions reliably. The route we usually recommend is to wrap the COBOL core with APIs so new digital products can use it, then decide later whether to migrate functions off it in phases or replace it with a modern vendor core. The right route depends on how much the old core limits your roadmap.
Banking software uses several programming languages: COBOL on older mainframe cores, Java and C# in many core and back-office systems, and modern stacks for new services and channels. Our engineers build with Node.js, Python, Ruby on Rails and Django on the backend and React, React Native and Flutter for web and mobile, and they connect to existing cores through APIs, whatever language those cores are written in.
Banks typically run a core banking system as the ledger and system of record, with online and mobile banking channels, payment processing, lending software, KYC and AML tools, a CRM, and reporting and analytics platforms connected to it. Many of these systems come from vendors. The software that connects and extends them is often custom-built, and that is where most of our banking projects sit.
The cost of custom banking software development is driven mainly by the layer you change, the state of your existing core, the number of systems you integrate with and your regulatory footprint. A new digital channel on a stable core costs far less than a core migration. The team model matters too, because a Dedicated Team, Team-as-a-Service or a fixed project scope each spread cost differently. A Discovery call is the quickest way to an estimate for your situation.
How long custom banking software takes depends on the layer and the scope. Adding a digital product on top of your existing core moves much faster than an integration programme, and core modernisation is the longest route of all. We plan in phases that each deliver working software, so you see progress early rather than waiting for one large release. After discovery, you get a roadmap based on your own systems and scope.
We keep banking software secure and compliant by designing for the rules from the start: encryption, access control and audit trails for PCI DSS and GDPR, strong customer authentication for PSD2, and monitoring that supports AML obligations. Security is tested throughout the build, not only before release. Your bank keeps the licence and the regulatory accountability; our role is to build systems that make meeting those obligations straightforward.
You do. On Prostrive's standard contracts, including Dedicated Teams, Team-as-a-Service and Project-Based Development, the client owns the code and the intellectual property of a custom build. Combined with the absence of long-term contracts, that means you can scale the team, change the collaboration model or bring your banking software in-house without being locked in.
An external development team should work inside your change control and security review, not around them. Prostrive engineers use your tools, join your standups and follow your release process, so every change goes through the same review and approval as your in-house work. Western on-site management in our hubs keeps the team accountable to those standards day to day.
You get started with a Discovery call. We talk through the change your bank needs, your current core and integrations, and any regulatory deadline you are working towards. From there, we propose a scope, a first step at the right layer and the team setup that fits, whether that is a Dedicated Team, Team-as-a-Service or Project-Based Development.
