FinTech Developer Interview Questions

Financial Systems Overview

Understanding the core financial systems is essential for FinTech developers:

• Banking Systems: Core banking, digital banking, and banking-as-a-service
• Payment Infrastructure: Card networks, ACH, wire transfers, real-time payments
• Capital Markets: Trading systems, exchanges, order management
• Lending Platforms: Credit scoring, loan origination, servicing systems
• Insurance Technology: Policy management, claims processing, underwriting

FinTech Business Models

Different FinTech segments have unique business models and technical requirements:

• Digital Banking: Neobanks, challenger banks, and banking platforms
• Payment Processing: Payment gateways, digital wallets, P2P payments
• WealthTech: Robo-advisors, investment platforms, portfolio management
• LendingTech: P2P lending, alternative credit, digital mortgages
• InsurTech: Digital insurance, parametric insurance, insurance marketplaces

Financial Data & Analytics

Financial data management has unique requirements and challenges:

• Market Data: Real-time and historical price data, reference data
• Transaction Data: Payment records, trading activity, account movements
• Customer Financial Data: Account information, credit history, financial behavior
• Risk Analytics: Credit risk, market risk, fraud risk modeling
• Regulatory Reporting: Financial statements, compliance reports, audit trails

Payment Systems & Processing

Payment technology is a core component of many FinTech applications:

• Payment Gateways: Integration with Stripe, PayPal, Adyen, Braintree
• Card Processing: Authorization, clearing, settlement, tokenization
• Alternative Payments: Digital wallets, QR codes, buy-now-pay-later
• Bank Transfers: ACH, SEPA, Faster Payments, wire transfers
• Payment Security: PCI DSS compliance, 3D Secure, fraud detection

Financial APIs & Integration

Modern FinTech relies heavily on API integrations:

• Banking APIs: Open banking, account information, payment initiation
• Payment APIs: Card processing, alternative payments, reconciliation
• Market Data APIs: Price feeds, financial news, economic indicators
• KYC/AML APIs: Identity verification, sanctions screening, PEP checks
• API Security: OAuth, API keys, mutual TLS, rate limiting

Financial Data Management

Handling financial data requires special considerations:

• Decimal Precision: Currency handling, rounding strategies, avoiding floating-point errors
• Data Consistency: ACID transactions, eventual consistency challenges
• Data Reconciliation: Balancing accounts, matching transactions
• Audit Trails: Immutable records, change tracking, regulatory requirements
• Data Retention: Compliance requirements, archiving strategies

Security & Compliance

Financial applications have stringent security and regulatory requirements:

• Data Protection: Encryption, tokenization, data minimization
• Authentication & Authorization: MFA, risk-based authentication, fine-grained access control
• Fraud Prevention: Transaction monitoring, behavioral analytics, machine learning
• Regulatory Compliance: KYC, AML, GDPR, PSD2, SOX
• Security Testing: Penetration testing, security code reviews, compliance audits

Financial Domain Knowledge

• Explain the difference between ACH and wire transfers.
• How does the credit card authorization and settlement process work?
• What are the key components of a core banking system?
• Explain the concept of KYC (Know Your Customer) and why it's important in FinTech.
• What are the main challenges in implementing a real-time payment system?

Technical Implementation

• How would you handle currency conversions and ensure accuracy in financial calculations?
• Describe your approach to implementing a secure payment processing system.
• How would you design a system that needs to integrate with multiple banking APIs?
• What strategies would you use to ensure data consistency in a distributed financial system?
• How would you implement a transaction reconciliation system?

Security & Compliance

• What is PCI DSS compliance and how would you ensure your payment application meets its requirements?
• How would you implement a secure authentication system for a banking application?
• What approaches would you take to detect and prevent fraudulent transactions?
• How would you handle sensitive financial data to comply with data protection regulations?
• Explain how you would implement audit logging in a financial application.

Architecture & Scalability

• How would you design a high-availability payment processing system?
• What architectural patterns would you use for a system that needs to process thousands of financial transactions per second?
• How would you handle database transactions in a microservices architecture for financial applications?
• Describe your approach to disaster recovery for a critical financial system.
• How would you design a system that needs to integrate real-time market data?

Emerging Technologies

• How could blockchain technology be applied to improve traditional financial processes?
• What are the potential applications of machine learning in fraud detection?
• How would you implement a smart contract for a financial application?
• What are the challenges of implementing open banking APIs?
• How could AI be used to improve customer experience in financial applications?

Payment Processing

• Stripe: Comprehensive payment platform with extensive API
• PayPal/Braintree: Global payment solutions with multiple payment methods
• Adyen: Enterprise payment platform with global reach
• Square: Payment processing with focus on small businesses
• Plaid: Financial account linking and verification

Banking Infrastructure

• Galileo: Banking and payments API platform
• Marqeta: Card issuing and processing platform
• Dwolla: ACH transfer API and payment infrastructure
• Finicity: Financial data aggregation and insights
• Mambu: Cloud banking platform

Financial Data & Analytics

• Refinitiv/Bloomberg: Market data and financial information
• Snowflake: Data warehousing for financial analytics
• Databricks: Unified analytics platform for financial data
• Kx Systems: Time-series database for financial analytics
• Tableau/Power BI: Data visualization for financial reporting

Security & Compliance

• Jumio: ID verification and KYC solutions
• Feedzai: Fraud detection and anti-money laundering
• Trulioo: Global identity verification
• Sift: Digital trust and safety platform
• Forter: E-commerce fraud prevention

Digital Banking

Modern banking platforms and services:

• Mobile banking applications and digital-only banks
• Banking-as-a-Service (BaaS) platforms
• Personal financial management (PFM) tools
• Account aggregation and financial dashboards
• Embedded finance and banking APIs

Payments & Transfers

Solutions for moving money efficiently:

• Mobile payment applications and digital wallets
• Peer-to-peer (P2P) payment platforms
• Cross-border payment and remittance services
• Point-of-sale (POS) and payment terminal solutions
• Buy-now-pay-later (BNPL) services

Investment & Wealth Management

Technology for investing and managing assets:

• Robo-advisors and automated investing platforms
• Stock trading and investment applications
• Portfolio management and tracking tools
• Alternative investment platforms (real estate, private equity)
• Cryptocurrency exchanges and wallets

Lending & Credit

Innovative approaches to lending and credit:

• Digital lending platforms and loan origination systems
• Peer-to-peer (P2P) lending marketplaces
• Alternative credit scoring and underwriting
• Buy-now-pay-later (BNPL) and point-of-sale financing
• Digital mortgage and real estate financing

Blockchain & Cryptocurrency

Decentralized financial technologies:

• Cryptocurrency exchanges and trading platforms
• Digital asset custody and wallet solutions
• Decentralized finance (DeFi) applications
• Blockchain-based payment and settlement systems
• Tokenization platforms for traditional assets