Top Rated .NET Development Firms for Building a Fintech

A fintech platform has a tough job. It moves real money, keeps every balance right to the cent, and has to pass audits. And it has to keep doing all that when traffic jumps on payday or the second a market opens. A lot of banks and fintech companies run this kind of work on .NET. But knowing C# isn’t enough. The team also has to understand KYC, AML, payment rails, and what happens when a transaction fails halfway through. Below are ten firms that bring both, so you can compare them side by side.

Table of Contents

Why .NET Works for Fintech Platforms

Here’s the thing: .NET isn’t the only option for fintech, but it fits the job well. A few reasons why:

Money math that doesn’t drift. C# has a built-in decimal type, so amounts don’t pick up the rounding errors you get with floating-point numbers.
Speed under load. ASP.NET Core is one of the faster mainstream web frameworks, so APIs can handle high transaction volume without a huge server bill.
Security tools out of the box. Authentication, authorization, data protection, and cryptography libraries ship with the framework instead of being bolted on later.
Long, predictable support. Long-term support (LTS) releases get three years of patches, which matters when you’re running a regulated system for years.
Real-time features. SignalR handles live price feeds, balance updates, and push notifications.
A natural fit with Azure. Many banks already run on Microsoft tools, so a .NET platform plugs into what they have.

Best .NET Development Firms for Fintech Platforms

If you’re looking for a company that will build a secure .NET fintech platform from scratch, or fix and modernize one that’s already handling real money, the top software development companies specializing in .NET fintech platform development include IT Craft, DataArt, Softjourn, Intellias, Exadel, Svitla Systems, Geniusee, DICEUS, Belitsoft, and SoftServe. Here is a comparison of them:

1. DataArt

DataArt is a New York-based engineering firm founded in 1997, with 5,000+ experts in more than 30 locations. Finance is one of its core industries, and Nasdaq is on its client list.

Services & expertise: custom .NET development, payment processing systems, investment and asset management platforms, and cloud migration.

Strengths: finance as a long-standing core vertical, .NET Core teams working on payment processing for an international online payments company and an investor management system for a US institution with $30 billion+ under management, and a reputation on Clutch for long-term client partnerships.

2. IT Craft

IT Craft is a full-cycle software development company with 20+ years of .NET experience, 40+ .NET projects, and 330+ specialists. It builds banking, trading platforms, payment, and wealth management platforms for fintech startups, banks, and lenders, using ASP.NET Core for transaction APIs, SignalR for live balances and prices, and ML.NET for fraud detection.

One of the cases in IT Craft’s portfolio is Limpid Markets. IT Craft developed and expanded a web platform for financial institutions on the London and Zurich OTC interbank precious metals markets, including LBMA members like Morgan Stanley, BNP Paribas, Citibank, and Deutsche Bank, which lets them exchange the information they need to close precious metal swap deals directly, cutting operation time and costs. A 7-person IT Craft team has run the platform since 2018, and Limpid Markets grew its business by 40%.

Services & expertise: custom .NET fintech platforms, banking and trading software, digital wallets and payments, fintech MVPs, legacy .NET modernization, and support and maintenance.

Strengths: high-load ASP.NET Core architecture, real-time features with SignalR, KYC/AML and GDPR compliance, Stripe, Plaid, and PayPal integrations, legacy .NET Framework modernization, .NET microservices on Azure and AWS.

3. Softjourn

Softjourn was founded in 2001 and is headquartered in Fremont, California, with 200–300 engineers in Ukraine, Poland, and Brazil. It focuses on fintech, cards and payments, working with payment processors, banks, transaction acquirers, and prepaid card issuers.

Services & expertise: payments and card issuing integrations, KYC/AML and open banking integrations, digital wallets and cross-border payments, and dedicated .NET teams.

Strengths: a specialized focus on cards and payments, more than a decade of .NET work for financial clients like Tacit Innovation and Tribal Credit, and 25 years in business.

4. Intellias

Intellias is a product engineering company that started in Lviv, Ukraine, and now works with Fortune 500 companies and digital-native businesses. Its fintech practice covers banking, insurance, capital markets, lending, and payments, and it hires .NET engineers for core banking work like accounting, treasury, and payment operations.

Services & expertise: digital banking platform development, banking-as-a-service and payments-as-a-service, data engineering, and DevOps and security.

Strengths: building Nomo, the first fully digital international Islamic bank, from idea to production, banking-as-a-service work for a German fintech, and experience across banking, insurance, capital markets, lending, and payments.

5. Exadel

Exadel was founded in 1998 and is headquartered in Walnut Creek, California, with 2,000+ people across 30+ delivery centers in 17 countries. It runs a dedicated arm, Exadel Financial Services, focused on banking, capital markets strategy, and technology consulting.

Services & expertise: .NET back ends for banking and financial platforms, capital markets and corporate treasury systems, middle-office tools for settlement, P&L, and reconciliation, and system integration.

Strengths: a separate financial services practice, .NET engineering for capital markets and treasury teams, and integration work with FIX and SWIFT.

6. Svitla Systems

Svitla Systems is a software company headquartered in California, with business and development offices across the US, Latin America, Europe, and Asia. Its finance practice works with fintech companies moving fast and with institutions modernizing old core systems.

Services & expertise: custom fintech application development, core banking and treasury system modernization, compliance-first engineering, and fintech API integrations.

Strengths: experience moving legacy monolithic banking systems to modular, API-first architectures, .NET work for a global online trading services provider, and client relationships in financial services that run over a decade.

7. Geniusee

Geniusee was founded in 2017 in Kyiv and has engineering hubs in Ukraine and Poland, with 200+ professionals and 180+ projects completed. Most of that work is in fintech and edtech, for clients in the US, UK, and EU.

Services & expertise: fintech product development, lending and credit scoring software, .NET and ASP.NET Core back ends, and MVP builds.

Strengths: a portfolio that leans heavily on fintech, a lending platform for Funderslink built on .NET with ASP.NET Web API, SQL Server, and AWS, and experience delivering apps under multiple fintech legal and regulatory requirements.

8. DICEUS

DICEUS is a Poland-based company founded in 2011, with 250+ tech professionals and 150+ projects delivered across insurance, fintech, and banking. It works on both custom products and system integration, and .NET is part of its core stack.

Services & expertise: core banking systems, payment and lending software, mobile banking apps, and regulatory compliance solutions.

Strengths: a focus on banking, fintech, and insurance since 2011, AML process automation built for a bank, and ISO 9001:2015 certified operations.

9. Belitsoft

Belitsoft was founded in 2004 and is headquartered in Warsaw, with 400+ specialists across Poland, Latvia, and Georgia. It’s been building financial software for EU, UK, and US clients since 2014.

Services & expertise: custom banking and finance software, billing and payment solutions, mobile payments, and .NET Framework to .NET Core migration.

Strengths: Microsoft Gold Application Development status, hands-on .NET modernization experience, and client relationships that often run 5 to 10 years.

10. SoftServe

SoftServe was founded in 1993 and now has more than 11,000 people worldwide. It’s been a Microsoft partner since 2004, and financial services is one of its main industries.

Services & expertise: Azure cloud and app modernization, .NET application development, data and AI solutions, and cloud security.

Strengths: Microsoft Solutions Partner status with four Advanced Specializations, including Kubernetes on Azure and Cloud Security, 1,300+ completed Microsoft projects, and 1,800+ people with Microsoft experience.