Fintech Case Study

How Trezy Transformed Financial Data Processing with Arkency's Event-Driven Approach

Trezy × Arkency — from unreliable webhooks and race conditions to a fully deterministic, event-sourced financial system.

The Challenge

Trezy, a fintech startup helping small business owners manage their cash flow, faced a growing challenge. Their existing system, built on a traditional CRUD-based approach, struggled to keep up with real-time financial data processing.

  • Webhooks from multiple third-party banking providers were unreliable, leading to delays and data inconsistencies.
  • Transaction classification was plagued by race conditions, causing inaccurate financial records.
  • Cashflow reports were limited to monthly views, leaving business owners without granular insights for day-to-day decisions.

As Trezy grew, these limitations became bottlenecks, making it clear that a fundamental shift in their architecture was necessary. That's when Arkency stepped in to help.

The Turning Point

Trezy needed a system that could:

  1. 1

    Ensure reliable and scalable webhook processing while maintaining data integrity.

  2. 2

    Accurately classify transactions in real-time without concurrency issues.

  3. 3

    Provide instant and always-available cashflow reports at different time intervals.

Arkency proposed a shift to Event Sourcing and Event-Driven Architecture, leveraging Domain-Driven Design (DDD) principles. This would not only solve the immediate pain points but also future-proof Trezy's financial data infrastructure.

The Transformation

1. Reliable Webhook Processing

  • Every incoming webhook stored as an immutable event — no data lost.
  • Events processed asynchronously, reducing system load and ensuring stability.
  • Past events reprocessable if a provider failed or changed format.

2. Accurate Transaction Classification

  • Aggregates enforced strict business rules to prevent misclassifications.
  • Process Managers orchestrated the classification workflow, eliminating race conditions.
  • Classification became deterministic and auditable, improving trust in financial data.

3. Scalable Cashflow Reporting

  • Reports precomputed from event streams instead of on-demand.
  • Expanded from monthly to daily, weekly, quarterly, and yearly cashflow insights.
  • Reports available instantly, enhancing decision-making for small business owners.

Results

  • Webhook processing became fully reliable, reducing errors and improving data ingestion speed.

  • Financial classification was now fully deterministic, eliminating inconsistencies.

  • Cashflow reports became instantly available, increasing their usability for business owners.

  • Scalability improved, allowing Trezy to integrate new financial data sources with ease.

Why Arkency?

Event Sourcing Expertise

Proven solutions for real-time data systems.

Deep Fintech Experience

Understanding the nuances of financial data integrity and compliance.

Business-Driven Approach

Focused on outcomes that matter to both developers and decision-makers.

Long-Term Partnership

Continuous improvement and adaptation as Trezy scaled.

Ready to Transform Your Financial System?

If you're facing similar challenges with financial data processing, let's talk.