Fintech is one of the most exciting and fastest-moving sectors in mobile app development. It is also one of the most technically demanding. Building a financial app that users trust requires a depth of expertise that goes well beyond standard mobile development. Security, compliance, and performance are not optional extras; they are foundational requirements.
The is home to one of the world’s most dynamic fintech ecosystems. Stakk has built financial applications across payment processing, personal finance management, investment platforms, and Open Banking integrations.
What Makes Fintech App Development Different?
Fintech app development introduces challenges that consumer apps simply do not face. FCA regulation, PSD2 compliance, GDPR requirements for financial data, PCI-DSS standards for payment processing, and Open Banking API integration all require specialist knowledge. A generic mobile development agency without fintech experience will almost inevitably miss requirements. As a result, this can cost enormous amounts to fix later.
Security Is Non-Negotiable in Fintech Apps
- End-to-end encryption — all data in transit and at rest must be encrypted to industry standards.
- Biometric authentication — Face ID and fingerprint authentication significantly reduce fraud risk.
- Session management — automatic session timeouts and re-authentication protect users on shared devices.
- API security — all third-party financial APIs must be integrated with proper authentication, rate limiting, and error handling.
Open Banking and PSD2 in Fintech Apps
The Open Banking framework, built on PSD2 standards, allows FCA-regulated apps to access bank account data. In addition, it allows them to initiate payments directly through secure APIs. Stakk’s developers have extensive experience integrating Open Banking APIs. For example, they have worked with providers such as TrueLayer and Plaid. These integrations power account aggregation, payment initiation, and personal finance features.
🔐 BUILD A FINTECH APP THAT EARNS TRUST
Security. Compliance. Performance. Stakk’s fintech development team understands what it takes to build financial products that users and regulators trust.
Frequently Asked Questions
What fintech businesses need to know before building a financial mobile app.
What is fintech app development?
Fintech app development is the process of building mobile applications for the financial services sector, including payment processing apps, personal finance management tools, banking platforms, investment apps, insurance products, and Open Banking integrations. Fintech development requires specialist knowledge of financial regulations, security standards, and API integrations that go well beyond standard mobile development.
How much does it cost to build a fintech app?
Building a fintech app in the typically costs between £60,000 and £500,000+ depending on the complexity of the financial features, the regulatory requirements, and the level of security infrastructure required. A simple personal finance MVP might cost £50,000 to £80,000, while a fully regulated payment or banking platform with FCA authorisation requirements can exceed £300,000 to £500,000.
Does my fintech app need to be FCA regulated?
Whether your fintech app requires FCA authorisation depends on the financial services it provides. Apps that facilitate payment initiation, account information services, lending, investment advice, or insurance products typically require FCA authorisation or registration under the relevant permissions. We strongly recommend obtaining independent legal advice on your regulatory obligations before development begins, as the architecture of your app must be designed to support compliance from the outset.
What is Open Banking and how does it work in apps?
Open Banking is a regulatory framework that requires banks to provide secure API access to account data and payment initiation for FCA-authorised third parties. In practice, fintech apps use Open Banking APIs — often accessed through aggregator platforms like TrueLayer or Plaid — to display bank balances, transaction histories, or initiate payments directly from a user’s bank account without needing card details.
What security standards should a fintech app meet?
A fintech app should meet PCI-DSS standards for payment card data if processing card payments, GDPR requirements for all personal financial data, FCA cybersecurity expectations for regulated firms, OWASP Mobile Security Top 10 best practices, and ISO 27001 information security management principles. End-to-end encryption, multi-factor authentication, and rigorous penetration testing are baseline requirements for any credible financial application.
How do I handle KYC and AML in a fintech app?
Know Your Customer (KYC) and Anti-Money Laundering (AML) processes in fintech apps are typically implemented using third-party identity verification APIs — such as Onfido, Jumio, or Sumsub — that automate document verification, facial recognition, and sanctions screening. Your development team integrates these APIs into the onboarding flow, and your compliance team sets the risk thresholds and decision rules for approval.
Can Stakk build a payment processing app?
Yes, Stakk has expert experience building payment processing features for fintech apps, integrating with providers including Stripe, Braintree, Adyen, and direct Open Banking payment initiation APIs. Payment flows require careful UX design, rigorous security testing, PCI-DSS compliance considerations, and thorough error handling to ensure reliability in production environments.
How long does it take to build a fintech app?
A fintech app typically takes between 6 and 18 months to build depending on complexity, regulatory requirements, and the number of financial API integrations involved. The additional time compared to consumer apps reflects the more extensive security architecture, compliance review, penetration testing, and app store review processes that financial applications require.
What technology stack should I use for a fintech app?
A typical fintech mobile app uses Swift or Kotlin for native iOS and Android development, or React Native or Flutter for cross-platform, with a secure cloud back-end on AWS or GCP using Node.js, Python, or Go. Financial data should be stored in encrypted databases with strict access controls, and all communications should use TLS 1.3. The specific stack depends on your feature set, scalability requirements, and existing infrastructure.
How do I attract fintech investment with a mobile app?
To attract fintech investment, your mobile app needs to demonstrate a credible regulatory strategy, evidence of user demand (even at MVP stage), a clear monetisation model, and a defensible technical architecture. Investors in fintech are particularly focused on compliance and security — a well-built, FCA-aware product from a credible development partner is a significant asset in investment discussions.
Key Takeaways
- Fintech app development requires specialized knowledge due to regulatory and compliance challenges that typical consumer apps do not face.
- Security is crucial; implementing end-to-end encryption, biometric authentication, and proper API security is non-negotiable.
- Open Banking and PSD2 frameworks enhance fintech apps by allowing secure access to bank data and payment initiation.
- The cost of building a fintech app typically ranges from £60,000 to £500,000, depending on complexity and regulatory needs.
- Stakk offers extensive experience in fintech app development, ensuring security, compliance, and performance throughout the process.
🔐 YOUR FINTECH IDEA DESERVES EXPERT BUILDERS
From Open Banking integrations to payment flows and FCA-aware architecture — Stakk has the fintech expertise your project needs. Get a free consultation.
About the Author
| Jack Tyson | Director, Stakk Jack Tyson is the Director of Stakk and has spent 12 years building mobile applications for start-ups, scale-ups, and global brands. With hands-on experience across iOS, Android, and cross-platform development, Jack brings both technical expertise and commercial insight to every project. 🔗 Connect with Jack: LinkedIn URL |
Blog Post 108 | fintech app development | Stakk | Published: June 2026
Estimated reading time: 7 minutes
