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Backend Engineering Consultancy

Java Systems
Engineer

Real-time trading systems, high-performance APIs,
and cloud-native architecture built to last under load.

Chipping, Lancashire · Available for Contract · 20 Years Delivering Systems
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001 — About

Backend Systems
Engineer

I build backend systems for performance-critical environments. My work focuses on real-time data processing, trading infrastructure, and API platforms where inefficiency compounds quickly and correctness is non-negotiable.

Over 20 years I've delivered systems across financial trading, energy, retail, and government — from streaming Betfair market data to event-driven pipelines on AWS. The common thread: systems that behave predictably under load.

I work across the full backend stack — architecture through implementation — with a bias toward simplicity, observability, and operational correctness over clever abstractions.

Engineering Philosophy

  • Performance is a feature, not an afterthought
  • Simplicity beats unnecessary abstraction
  • Systems must be observable to be trusted
  • Build only what is needed — but build it well
Full Bio →
002 — Capabilities

What I Build

01
Real-Time Data Systems
Streaming architectures designed for low latency and high throughput. Event-driven pipelines that hold correctness at volume.
02
Trading Infrastructure
Order book modelling, price formation, and execution logic. Exchange API integration: Betfair, Betdaq, Smarkets.
03
API Platform Design
Robust, scalable APIs built with Java and Spring Boot. Designed for reliability, clear contracts, and long-term maintainability.
04
Cloud Infrastructure
AWS systems using CDK, Lambda, and S3. Event-driven patterns and cost-efficient scalable pipelines without over-engineering.
05
Performance Engineering
Optimisation at system and code level. Concurrency, GC tuning, and latency analysis for systems where milliseconds matter.
06
Architecture & Design
Hexagonal architecture, DDD, CQRS, and event sourcing applied where they reduce complexity — not as cargo cult.
All Capabilities →
003 — Work

Selected Work

Trading System
Betfair Trading Platform
  • Real-time market stream processing via Betfair Streaming API
  • Order flow analysis and price movement detection
  • Momentum and imbalance indicators using TA4J
  • Automated strategy execution with risk controls

Focus

Latency Signal Quality Execution Efficiency
Data Platform
Historical Data API
  • S3-based storage with compressed CSV at scale
  • Metadata indexing and local caching layer
  • Fast query API without traditional database overhead
  • Designed for cost efficiency and analytical throughput

Focus

Cost Efficiency Fast Retrieval Scalable Design
All Projects →
004 — Stack

Technical Focus

Core
Java 21 Spring Boot Spring Cloud Maven Gradle JUnit 5 Testcontainers
Messaging & Streaming
Apache Kafka AWS SNS / SQS RabbitMQ Betfair Streaming API TA4J
Cloud & Infrastructure
AWS CDK AWS Lambda AWS S3 DynamoDB Docker GitHub Actions
Data
PostgreSQL MongoDB Redis Hibernate Spring Data
Observability
Micrometer Prometheus Grafana Spring Actuator Resilience4j
Full Stack →
005 — Writing

Technical Writing

Dec 20, 2025 Architecture
Object-Oriented vs Functional Programming (And Why the Argument Is Wrong)
Every few years, the OO vs Functional Programming debate resurfaces, usually framed as a zero-sum argument....
 Dec 20, 2025 Architecture
Hexagonal vs Clean Architecture in Spring Boot
Once you move beyond simple CRUD services, architecture choices start to matter. Two patterns that frequent...
 Dec 15, 2025 Architecture
Hexagonal Architecture for Real-World Systems
Working on long-lived, high-stakes systems — from real-time financial data pipelines at Mosaic Smart Data t...
All Posts →
006 — Contact

Work Together

Available for consultancy and contract work. If you are building systems where performance and correctness matter — trading platforms, data pipelines, high-throughput APIs — get in touch.

Get in Touch → Hire Me
GitHub Writing jacksosa76@gmail.com