Simon Cullen
Principal Data Engineer

Simon Cullen

Building data platforms that process $2B+ annually with 99.99% uptime

$2B+ Annual Transactions
10+ Years Experience
99.99% System Uptime
+300% Performance Gains
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About

Data Engineering
at Scale

Principal Data Engineer with expertise in designing and maintaining large-scale data platforms. Proven track record of implementing mission-critical systems processing billions of dollars annually.

Currently leading data engineering initiatives at OptumRx (UnitedHealth Group), ensuring 24/7 uptime of mission-critical pricing systems.

Tech Stack

Python
Azure
Databricks
SQL
Docker
Kubernetes
Airflow
Snowflake
Spark
Terraform
dbt
Kafka
Experience

Career Timeline

Principal Data Engineer

OptumRx @ UnitedHealth Group
2023 — Present
$2B+ Transactions
24/7 Uptime
300% Faster

Architecting high-availability data platforms for pricing and underwriting. Leading migration from legacy R codebase to modern Python-based pipelines using Azure Data Factory and Databricks.

Senior Data Analyst — Compliance

Kraken Digital Asset Exchange
2023 — 2024
TB+ Data
AI Detection

Designed automated compliance reporting dashboards. Engineered data pipelines for cryptocurrency transaction monitoring. Led data operations for regulatory audits and legal cases.

Business Intelligence Developer

Susquehanna International Group
2017 — 2022
$M+ Saved
Real-time ETF

Architected high-volume ETL pipelines for trading operations. Developed real-time ETF basket composition system. Created trading anomaly detection preventing significant financial losses.

Projects

Impact-Driven Work

Data Engineering Cloud

Mission-Critical Pricing Platform

Problem

Legacy pricing systems with frequent outages threatening $2B+ annual bid processing

→
Solution

High-availability data platform with Azure Data Factory and Databricks

→
Result

99.99% uptime over 18 months

Migration Performance

Legacy System Modernization

Problem

Aging R-based ETL pipelines with 6+ hour processing times

→
Solution

Complete migration to Python-based pipelines with Azure orchestration

→
Result

300% faster, under 2 hours

AI/ML Compliance

Crypto Anomaly Detection

Problem

Manual review of terabytes of transaction data for suspicious activity

→
Solution

AI-powered anomaly detection with real-time alerting

→
Result

90% less manual review

Real-time Trading

ETF Basket Processing

Problem

Batch processing causing pricing delays and arbitrage exposure

→
Solution

Real-time streaming pipeline with sub-second latency

→
Result

Zero arbitrage exposure

DevOps Automation

CI/CD Pipeline Automation

Problem

Multi-day deployment cycles with manual testing

→
Solution

CI/CD pipelines with automated testing and blue-green deploys

→
Result

Days → Minutes deployment

Data Warehouse Analytics

Snowflake Implementation

Problem

Siloed data across 15+ systems, inconsistent metrics

→
Solution

Enterprise Snowflake with automated ingestion and dbt

→
Result

Single source of truth

Technical Demo

REST API + Valkey

Live demonstration of a Go backend with Gin framework and Valkey (Redis-compatible) database. Features rate limiting, input sanitization, and scheduled data cleanup.

main.go 
func main() {
    router := gin.Default()
    
    // Rate-limited endpoints
    api := router.Group("/api")
    api.POST("/entries", 
        middleware.RateLimitMiddleware(), 
        handler.CreateEntry)
    
    router.Run(":8080")
}
Rate Limiting
XSS Protection
Auto Cleanup

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Credentials

Certifications & Education

Azure DP-900

Microsoft Azure Data Fundamentals

Databricks Lakehouse

Fundamentals Certification

Chainalysis Reactor

Blockchain Fraud Analysis

ITIL V3 Foundation

IT Service Management

Teradata Certified

Database Administration

Graduate Diploma IT

Dublin City University

M.Sc International Business

Dublin Institute of Technology

B.Sc Business Studies

Dublin Institute of Technology