Fintech Architecture • March 2025 • 7 min read

The ETD API

From Raw Data to Rich Experience

A showcase of engineering excellence in real-time transaction processing.

The Challenge: When Events Don't Arrive Together

In high-scale financial systems, transaction data arrives from different sources at different times. This timing mismatch is a critical architectural reality that must be solved to avoid delays or showing customers incomplete information.

FAP Event

Arrives Instantly

< 1 second

CDP Event

Arrives Later

100-400ms

Our Solution: A Three-Pillar Architecture

Pillar 1: Intelligent Data Ingestion

Orchestrates and correlates out-of-sync events from FAP and CDP streams using a smart temporal buffer.

99%

Event Join Rate

Exceeding 98% target

Pillar 2: Composite Key Innovation

Creates a unique 8-field "fingerprint" for every transaction, allowing for precise matching even in complex scenarios.

[Bank]|[Account]|[Amount]|[Date]|[Ref]...

98.2%

Matching Accuracy

Pillar 3: Real-Time Enrichment

Transforms raw, cryptic transaction data into a clear, customer-friendly story with merchant names, logos, categories, and locations.

Before: SQ *COFFEE SHOP

After: ☕ Starbucks #1234

How It Works: Intelligent Correlation Flow

Our system uses a sophisticated state machine to manage the temporal complexity. A smart, optimized correlation window ensures data is joined efficiently without compromising user experience.

Receive Event

Generate Key

Smart Wait

Join Data

Enrich

Serve via API

The Impact: By The Numbers

Performance Excellence

<100ms

API Response Time

40M+

Daily Transaction Capability

Join Success Rate vs. Target

Operational Efficiency

$50M+

Annual Savings

50%

Mainframe Traffic Reduction

150K+

Fewer Calls Monthly

Customer Experience

  • 📜
    Rich Details

    Clear merchant name, logo, category, and location for every transaction.

  • Real-Time Availability

    Sub-second enrichment for the vast majority of customer transactions.

  • 📱
    Better Mobile UX

    An enhanced, intuitive, and trustworthy transaction history.

The Teams Behind the Magic

This breakthrough was made possible by the seamless collaboration of three expert engineering teams, each mastering a critical layer of the architecture.

⚙️

BLR Team

The Data Orchestrators

💎

COL Team

The Enrichment Innovators

🏗️

DEL Team

The API Architects

Sources & Further Reading

Dive deeper into the raw research, architecture notes, and collaborative brainstorming that informed this case study.