MoneyLion's Digital Banking Platform Architecture

Introduction

MoneyLion is a leading financial technology company powering the next generation of personalized financial products and content, with a top consumer finance mobile app, and a premier embedded finance enterprise platform.

MoneyLion's mission is to give everyone the power to make their best financial decisions. Its products include:

• Mobile banking, with spending, saving, and credit-tracking tools

• Integrated consumer services, including payroll advance, earned wage access, and investing

• A financial product marketplace with third-party lending, credit card, and insurance offers

The Challenge

MoneyLion set out to build a system that could integrate its entire product line and meet strict federal regulatory requirements. The MoneyLion engineering team determined that for some of their products, the architecture would be a colossal feat, requiring an event-based system that can deliver integration and auditability for federal regulatory purposes, as well as domain-based partitioning and open-ended scalability for its growing product line and user base.

The Solution: An Event-Sourced Digital Banking Platform

Over the past couple of years, MoneyLion deployed Axon in two use cases: banking and payments.

Banking

MoneyLion's banking team runs these services on Axon Framework and Axon Server:

• Bank account management

• Physical card management

• Direct deposit switch service

• Transaction aggregation

• Payment service

• Cheque processing service

• Account statement service

• External authentication for surfacing account information

Payments

MoneyLion's payments team runs every internal and external fund transfer on Axon. Internally, this refers to fund transfers initiated by MoneyLion to facilitate membership fees, loan or other product repayments, or loan disbursement. Externally, this refers to fund transfers initiated by their customers. These fund transfers may involve debiting or crediting their customers using various payment methods such as ACH, Debit Card, or Demand Deposit Account.

MoneyLion runs the Axon stack alongside:

• AWS: Elastic Kubernetes Service (EKS), Relational Database Service (RDS), Simple Queue Service (SQS), Secrets Manager, Lambda

• Datadog, Redis, Flyway, DynamoDB

Transitioning to an Event-Driven Architecture and implementing event sourcing can be challenging, but the Axon Framework made it seamless. With its powerful, ready-to-use solutions, Axon (Framework and Server) reduced our workload with hundreds of hours of development, allowing us to concentrate on developing our core features. This streamlined approach has empowered our team to innovate faster and deliver exceptional results."

- Sachin Singh Yadav, Lead Engineer, MoneyLion

Technical Impact and Benefits

MoneyLion achieved scalability, flexibility, auditability, and high availability using Axon in combination with these other technology suppliers to build the foundation for its microservices design. MoneyLion identified the following benefits per use case:

Banking

• Auditability of each workflow

• Replayability for disaster recovery

• Loosely coupled services

Payments

• Auditability of every state change, built in rather than added on, which is essential when funds move.

• Replay of past events, so MoneyLion can build new read models it couldn’t anticipate in advance.

• Simpler handling of distributed transactions that span multiple payment contexts.

  
  

An Audit Trail Built Into Every Fund Transfer

When money moves, regulators and MoneyLion’s own teams need to know exactly what happened. Because every state change in its payment services is stored as an event, the record is the system itself, not a log written beside it. Any transfer can be traced back to the exact state behind it, which is the same record an automated decision in that flow would need in order to be explained.

Building Something Similar?

MoneyLion’s approach is how more financial teams now handle compliance: every state change is kept as an event, so the audit trail is the system itself rather than a log added later. See how Axoniq supports event sourcing for financial services, or how the same approach works for payments processing, where any balance at any moment is a query, not an investigation.