Fintech Software Development: A Complete Guide

Fintech software development is the building of payment systems, digital banks, loan platforms, and other tools that move, lend, store, or invest money. Unlike an online store, a fintech product must obey laws on card data, privacy, and money laundering. That’s why compliance must be built into the project’s architecture from the start.

Mistakes here are expensive. An error in a payment system can break financial regulations, which can lead to fines and lost customer trust. For that reason, when we provide fintech software development services, our team starts by reviewing the compliance requirements your legal advisors have set, then designs each feature to meet them.

Despite the strict rules, fintech firms are growing more than four times faster than traditional banks and insurers. According to BCG, the sector’s revenue passed half a trillion dollars in 2025, up 22% in a single year, and 74% of its 85 largest listed companies are profitable. If you’re building a financial product, start here: we’ll go through the main types of fintech software, the steps of a typical project, and the security rules to plan for.

What Types of Fintech Software Can You Build?

Most fintech projects fall into one of five groups, known as sub-verticals, each with its own products, rules, and technical challenges:

• Payments and digital wallets: These include checkout pages, digital wallets, seller payouts, and invoicing systems that allow people and businesses to send and receive money. For these products, choices made at the start are hard to change later, as we explain in our article on the payment gateway integration decisions founders regret. Redwerk has worked in this area before, building a webshop module for Orderstep, a Nordic invoicing platform that has processed deals worth 150 million Danish kroner.
• Digital banking: Mobile banking apps, online account opening, and the core systems that record every balance and transaction make up this group. Many established financial institutions still rely on software written decades ago, so adding new features is slow and risky. Our guide to the signs a legacy banking system needs digital transformation explains when an upgrade becomes necessary.
• Lending and credit: Lenders use this software to take loan applications, check whether a borrower can repay, and manage repayments and collections. More companies now let AI make those checks, and from December 2, 2027, the EU AI Act will treat such credit scoring as high-risk, which means stricter testing and human oversight. Our guide on what fintech founders should know before adding AI explains how to prepare.
• Wealth management and investing: This group covers investing apps, robo-advisors (services that manage a portfolio automatically), and advisor dashboards. Many of these products now let customers buy Bitcoin and other digital coins as well, which brings extra rules. Since July 1, 2026, any business offering such trades to EU residents needs a license under MiCA, the EU’s regulation for crypto-assets. Our MiCA compliance services guide companies through the licensing process.
• Insurtech: Insurers rely on software for online quotes, policy management, and claims handling. Policyholder files often contain health details, home addresses, and payment information, so privacy rules apply as strictly as in banking. Much of this work is repetitive and well suited to automation, especially settling payouts and underwriting (deciding whether to insure someone and at what price). Our guide to AI in insurance shows where insurers see the quickest returns.

Here’s how fintech software development differs across the five groups:

How Does the Fintech App Development Process Work?

The fintech app development process looks like other software work, except that compliance shapes every step. A typical project runs in five stages:

1. Scope the product and the rules together. Before coding starts, the team defines what the software must do and what regulations apply to your markets, data, and payments. Our discovery phase services turn those findings into a written scope, so compliance costs appear in the estimate from the beginning. You don’t need a finished specification before hiring us, because your team and ours work out the details together at this stage.
2. Design the architecture. Next, the team decides how the system is structured. For fintech, that structure must answer three questions: where customer information is stored, how it’s encrypted so outsiders can’t read it, and what activity is recorded for auditors.
3. Build and connect. Developers write the software in short cycles called sprints, usually two weeks long. The team also connects the product to payment providers, banks, and identity checks through APIs (application programming interfaces), the links that let two systems exchange data. Each connection takes extra time, because the company on the other side runs its own tests and must approve the setup before you can go live.
4. Test the calculations as well as the screens. Beyond checking that buttons work, the team confirms that every amount adds up, including refunds, fees, and currency rounding. Security specialists also run penetration tests, trying to break in the way a real attacker would. For VIP Auslan, a booking platform that also handles payroll and invoicing, we rebuilt the cancellation-fee logic and re-checked every payment flow after each change, which cut critical system errors by 90%.
5. Launch, then stay compliant. After release, auditors review the product every year, and card and privacy standards change over time. Each new version of a standard may require updates to your software, so plan a maintenance budget from the start.

How to Build Security and Compliance Into Fintech Software

Building security and compliance into fintech software involves two steps: finding out which rules apply to your product, then turning those requirements into daily development practices. Fintech software compliance means following the laws and industry standards that cover your business and being able to show an auditor that you do. Starting this work before development begins costs far less than fixing gaps after launch, because the rules decide how information is stored, who can see the data, and what gets recorded.

Security failures are getting more expensive. IBM’s latest study of organizations hit by a data breach put the average cost at $4.99 million per incident, a record high. Any app or platform that moves money is also a target for criminals, and our guide to payment fraud prevention compares building your own protection with buying a ready-made service. The next two sections explain what regulations matter most and what security measures put those requirements into practice.

The Rules Most Fintech Products Must Follow

Which rules apply depends on what your product does and where your customers live. The following come up most often:

• PCI DSS: the Payment Card Industry Data Security Standard, which covers any system that stores, processes, or sends card data. With version 4.x, 51 additional requirements became mandatory on March 31, 2025, including checks on the code that runs on checkout pages.
• KYC and AML: KYC (Know Your Customer) is the process of verifying each client’s identity, and AML (Anti-Money Laundering) covers watching transactions for signs of criminal funds. New EU rules in this area apply from July 10, 2027.
• Privacy laws: The General Data Protection Regulation (GDPR) sets requirements for how businesses collect, store, and delete personal data about people in the EU. In the US, the Safeguards Rule under the Gramm-Leach-Bliley Act (GLBA) requires financial companies to protect customer information and, since May 2024, to report breaches affecting 500 or more consumers to the Federal Trade Commission (FTC) within 30 days.
• SOC 2: short for System and Organization Controls 2, an independent audit of how well a company keeps data safe. No law requires the review, but banks and large clients often ask for the report before signing.
• DORA: the EU’s Digital Operational Resilience Act, in effect since January 17, 2025. The regulation requires financial firms to prepare for, survive, and recover from tech failures and cyberattacks, including problems at their cloud and software suppliers.
• Open banking rules: laws that let people share their account data with other apps. In the US, the Consumer Financial Protection Bureau is reconsidering its data-sharing rule (Section 1033), so final requirements are unknown. The EU’s new payment laws, the third Payment Services Directive (PSD3) and the Payment Services Regulation (PSR), are agreed but not yet in force.

If your product uses artificial intelligence, extra rules apply, and our AI compliance in finance blueprint explains the EU, US, and MiCA requirements.

What Security by Design Looks Like in Practice

Security by design means building protection into each feature as it is planned and coded. In practice, that involves five safeguards:

• Threat modeling every sprint: At the start of each two-week cycle, the team lists the ways new features could be attacked or misused and plans defenses ahead of coding. Redwerk applies this method whenever a project needs it.
• Encryption everywhere: Data is turned into unreadable code while it’s stored and while it’s sent between systems. Only authorized software with the correct key can read it, so a stolen copy is useless to an attacker.
• Least-privilege access: Each employee and system can reach only the data and functions a job requires.
• Audit trails: The system records every action involving money or customer data, including who acted and when.
• Privacy by default: The product collects only the data it needs and deletes old records on a set schedule, which is the basis of a GDPR-compliant architecture.

The SDLC best practices article shows how to apply these safeguards in each phase of the software development life cycle.

Redwerk regularly builds software under strict regulations. One example is Current, a system that US state and county human services agencies use to manage welfare benefits. We built it on ASP.NET Core, Angular, and Microsoft Azure and kept passwords and encryption keys in a separate, secured storage service. Ten agencies now run their programs on the platform, which is 100% compliant with the Americans with Disabilities Act (ADA), the US accessibility law.

How to Choose a Fintech Software Development Partner

Before you sign a contract with a development partner, ask these five questions:

• Which payment or banking APIs have you integrated? Ask for specific examples, such as a card processor, a service that pulls account data, or a core system at a lender.
• How does compliance fit into your process? A good answer explains how threat modeling, security reviews, and audit trails fit into the sprint schedule.
• Have you delivered in a regulated, high-stakes setting? Teams that have worked in payments, government, or healthcare have learned to document decisions and handle errors the way regulators expect.
• Do your developers already know the technology we use? A team that learns your tools while working on your project will be slower and cost more.
• How will you keep us informed? Weekly demos and one dedicated contact person matter most when your own staff isn’t technical.

Much of the software at banks and insurers is built with Microsoft products, so a partner skilled in .NET development and Azure cloud services can work with existing systems immediately. For data analysis, fraud detection, and AI features, the Python programming language is the usual choice. Redwerk staffs each new project with developers who already work with the client’s technology, which is why clients often mention how quickly our teams start delivering.

Some of that work ends up at major banks. For BlueCloud Technologies, we built Printer Interceptor, a .NET and C++ library that adds security watermarks to everything printed through the company’s ScreenID product. ScreenID’s customers include Crédit Agricole Group, National Bank of Egypt, and Commercial International Bank, and our code marks 800 image-rich pages in under 2 minutes.

Already have a fintech product? A software development audit will find its security and compliance gaps before you invest in new features.

Build Compliance Into Your Fintech Product From the Start

Fintech software development is as much about meeting regulations as it is about writing code. The partner worth choosing treats security as part of the design at every stage of the project. Redwerk works this way, with GDPR-compliant architecture and protection built into every phase, based on our experience with regulated, high-stakes projects.

Your legal and compliance advisors decide which rules your product must meet, and our engineers turn those requirements into system designs, features, and tests. Ready to start your fintech project? Schedule a call with our team.

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