Global Financial Institution

Modernizing a Legacy Financial Platform with Early AI-Assisted Engineering

AI
Clean Architecture
Platform Modernization
AI Assisted Engineering
Modularity
Cloud
Aws

Overview

Before AI coding assistants became mainstream and really good, we partnered with a global financial behemoth to modernize a mission-critical Fund Management and Administration platform built on legacy technologies - using AI.

This program stands out as an early enterprise adoption of AI-assisted software delivery, where LLMs were used not as experimental tools, but as practical accelerators in a large-scale modernization effort.

The Challenge

The client’s platform was critical to investor reporting and financial operations but faced severe limitations:

  • Built on Classic ASP and VBScript (near end-of-life)
  • ~500,000 lines of tightly coupled code
  • Business logic embedded within UI layers
  • Single-server deployment with no scalability
  • File system–dependent storage with no resilient backup
  • High infrastructure and maintenance costs
  • Limited internal understanding of system behaviour

At the time, late 2024, traditional migration approaches would have been slow, costly, and risky.

The Innovation: Early AI-Assisted Delivery

This program was initiated before coding agents became widely adopted.

We leveraged early LLM-based tools (such as Gemini) and initial versions of Copilot to:

  • Accelerate code translation from Classic ASP to ASP.NET MVC
  • Assist in identifying reusable patterns
  • Support developers in navigating a large, poorly documented codebase

Unlike today’s mature AI workflows, these tools required heavy human validation, making this a hybrid model of AI-assisted + engineering-led delivery.

The Approach

  1. AI-Accelerated Code Migration:
    Used LLMs to assist in translating legacy code while engineers validated and refactored outputs.
  2. Architectural Modernization
    • Migrated from coupled 2-tier to 3-tier MVC architecture
    • Introduced modular design and reusable components
    • Containerized applications using Docker
    • Enabled deployment on Kubernetes
  3. Cloud-Native Transformation
    • Migrated file storage from local systems to AWS S3
    • Enabled scalable backup and recovery
  4. Phased Delivery
    • Phase 1–2: Investment facing Portal
    • Phase 3–6: Admin Portal (internal operations)
  5. Custom Validation Framework:
    Built an automated framework to compare outputs between legacy and new systems—critical due to AI-assisted code generation.

Challenges of Early AI Adoption

Because this was done before modern AI tooling matured, the team navigated:

  • LLM hallucinations in generated code
  • Inconsistent translation of business logic
  • Poorly structured legacy HTML incompatible with modern frameworks
  • Limited access to real production data
  • Lack of mature AI debugging workflows

Outcome

✅ Investments Portal successfully deployed (November)

✅ Admin Portal deployed (January)

✅ No major production incidents post-release

✅ Cloud-native, scalable architecture achieved

✅ Significant improvements in maintainability

Impact

  • Reduced technical and security risk
  • Established a modern, extensible platform
  • Enabled future transformation (API-first, React-based UI)
  • Demonstrated real-world viability of AI-assisted engineering

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