Legacy App Modernization in Miami, FL

Financial Services / International Banking

A Miami-based international bank (specialising in US-Latin America private banking — $5.2B in assets, 42,000 client accounts, 280 employees) was constrained by a legacy core banking system. Legacy core: IBM AS/400-based core banking system installed in 1996 — running RPG programs with a green-screen interface. The system: processing $6.8B in annual transactions reliably with near-zero downtime. However: the system couldn't support mobile banking (no API layer for mobile app connectivity), couldn't integrate with modern payment networks (PIX, real-time ACH), couldn't support AI-powered compliance (batch screening only), couldn't provide real-time data for client-facing dashboards, and couldn't enable fintech partnership APIs. The core: a technology barrier preventing the bank from competing with modern private banking platforms and fintech alternatives. Client impact: high-net-worth clients expecting mobile portfolio access, instant international transfers, and digital document exchange — capabilities that competitors provided but this bank couldn't offer. Client attrition: 6.2% annually (vs. 3.8% industry average), with exit interviews consistently citing technology limitations. Relationship managers: spending 2+ hours daily on tasks that modern banking platforms would automate — manually compiling portfolio summaries, processing wire transfer requests through green-screen workflows, and printing statements for clients who couldn't access digital versions. Previous modernization attempt: a core replacement project attempted 3 years earlier — budgeted at $4.5M with an 18-month timeline. The project: cancelled after 14 months and $3.2M spent when it became clear the replacement system couldn't replicate critical workflows for Latin American correspondent banking. The failure: creating deep organisational skepticism about modernization.

We designed and executed a strangler fig modernization over 18 months. API layer (months 1-5). Core banking API: RESTful API layer built on top of the AS/400 — reading and writing core banking data through modern interfaces without modifying the RPG programs. The API: translating between the core's fixed-format data structures and modern JSON/REST conventions. API scope: account management (balances, history, holds), customer profiles (demographics, KYC data, preferences), transaction processing (internal transfers, wire instructions), and reporting (portfolio summaries, statements, regulatory data). Security: OAuth 2.0 authentication, request signing, and comprehensive audit logging — meeting OCC guidance for API security in banking. Performance: API responses in under 200ms despite the AS/400 backend — achieved through intelligent caching, connection pooling, and optimised RPG-to-API data retrieval programs. The API: tested extensively with parallel validation against direct-to-core data access — ensuring API data exactly matched core system data. Mobile banking application (months 4-9). Client mobile app: built on the API layer — portfolio overview, transaction history, wire transfer initiation, document access, and secure messaging with relationship managers. Bilingual: full English-Spanish capability with language detection and preference management. The app: providing the mobile access that clients had been requesting and competitors already offered. Biometric authentication: Face ID and fingerprint login — convenience expected by private banking clients. Secure document exchange: encrypted document sharing between clients and relationship managers — replacing the printing, scanning, and mailing that previously handled document exchange. Client dashboard: web-based portfolio dashboard providing real-time portfolio views, performance analytics, and market information — relationship managers sharing the same view with clients during consultations. Payment network modernization (months 6-12). Real-time payments: PIX (Brazil) and real-time ACH integration through the API layer — enabling same-day cross-border transfers that previously took 2-3 business days through SWIFT. The integration: connecting modern payment network adapters to the API layer, which translated payment instructions into core banking transactions. Wire processing: wire transfer workflow modernized from green-screen to web-based interface — relationship managers initiating wires through a modern form with automatic compliance screening, approval routing, and status tracking. Processing time: from 45 minutes per wire (green-screen entry, manual compliance check, supervisor approval through separate system) to 8 minutes (web form with embedded compliance and digital approval). Compliance modernization (months 10-18). Real-time screening: OFAC and sanctions screening integrated into the API layer — every transaction, new account, and wire transfer screened in real-time (under 500ms) rather than batch-screened overnight. ML risk scoring: machine learning model evaluating transaction risk based on amount, corridor, counterparty, and pattern analysis — replacing the binary flag/clear approach with risk-based decisions. False positive reduction: from 9.1% flag rate to 3.4% — the ML model better distinguishing genuine risk from normal international banking activity. Compliance dashboard: real-time compliance status, screening results, and regulatory reporting — replacing the batch reports and manual case management that previously consumed compliance staff time.

The modernization completed over 18 months with zero operational disruption. Client experience: mobile app adoption: 68% of active clients using the mobile app within 6 months of launch. Client satisfaction: improved 38% — mobile access, faster transfers, and digital document exchange addressing the primary complaints. Client attrition: from 6.2% to 3.1% annually — the modernized platform eliminating the technology gap that drove client departures. New client acquisition: 840 new accounts in the first year post-modernization (vs. 420 average in prior years) — modern capabilities enabling the sales team to compete effectively against technology-forward competitors. Operational efficiency: wire processing: from 45 minutes to 8 minutes per transaction (82% reduction). Relationship manager productivity: 2+ hours daily freed from manual tasks — redirected to client relationship building and portfolio advisory. Statement and report generation: from manual compilation to automated delivery — relationship managers accessing real-time client data rather than running overnight batch reports. Payment speed: cross-border transfers from 2-3 business days to same-day for PIX corridors and next-day for most Latin American destinations. Compliance: screening coverage: from overnight batch to real-time — every transaction screened before processing. False positive reduction: from 9.1% to 3.4% — compliance staff focusing on genuine risk rather than clearing false positives. Regulatory examination: next OCC examination noting significant improvement in compliance technology and monitoring capability. Legacy system status: the AS/400 core continues operating — now wrapped in modern APIs that enable capabilities it was never designed to support. The strangler fig: progressively handling more functions through the modern layer while the core handles foundational transaction processing. The approach: validated the organisation's preference for incremental modernization over risky replacement. Financial results: client retention improvement: $3.4M/year (reduced attrition from $5.2B AUM base). New client revenue: $2.1M/year (increased acquisition from modernized platform). Operational efficiency: $1.8M/year (wire processing, RM productivity, automated reporting). Compliance efficiency: $420K/year (reduced false positives, automated screening). Total annual impact: $7.72M/year. Modernization investment: $1.4M (over 18 months). Annual operations: $240K/year. First-year ROI (post-completion): 451%.