Corey Duffy
Senior Software Engineer | Tech Lead
Over a decade writing software and building robust systems. Currently building AI products and digital solutions for enterprise clients, while keeping the robots honest.
About
Hey, I'm Corey, and I've worked as a software engineer from the moment I left school (over a decade ago now), initially working full-time while studying for my degree.
Since then, I've worked across a range of companies, startups and scale-ups on back-end services, front-ends, automated testing, DevOps, DevSecOps, AI/LLMs and everything in-between.
What initially attracted me to software development was the idea of being able to create and build whatever I could think of. What has kept me engaged with software development is the sense of honing a craft.
Across all of my interests, be it software engineering, running or strength-training, I love the sense of progression. I love the ability to learn, adapt and improve, and see those improvements over time.
In this space, there is always more to learn, there are always ways to grow.
Anything I write here is in pursuit of that improvement. It's my way of learning, re-learning or confirming what I already know.
I definitely don't have all the answers, but (hopefully, at least) I'm always improving, and hopefully there's something useful here for others too.
Writing
Notes on software engineering, AI, and building things.
- How I avoid becoming a stranger in my own codebase
- What to do when your knowledge agent doesn't seem so knowledgeable
Experience
Senior Software Engineer
Brightbeam Apr 2025 – PresentAI and digital intelligence solutions for enterprise clients
- Led a customer support agent project from concept to completion, enabling client to win Investment in Innovation Award
- Developed working proof-of-concepts for agentic solutions and computer vision projects, enabling clients to visualise AI capabilities and achieve stakeholder buy-in
- Planned and architected multiple AI solutions for enterprise clients with complex security requirements
- Built reusable infrastructure scripts and shared tooling to accelerate team delivery
Product Engineer
Fluent Aug 2024 – Nov 2024AI Text-to-SQL product development
- Improved generated SQL accuracy by over 75% through metrics layer implementation
- Halved response time and significantly improved LLM output quality through prompt tuning
- Delivered new BI features improving customer retention
- Conducted customer interviews to establish product-market fit
Software Developer
m3ter Oct 2022 – Aug 2024Usage-based billing platform development
- Reduced console search time from over a minute to under a second via new search service
- Reduced ad-hoc bill calculation time from 30+ minutes to seconds
- Solved critical security issue with "support user" access system
- Addressed high-risk architectural issues ensuring stability under vast data loads
Software Engineer
Uleska Nov 2020 – Oct 2022Security tool automation platform
- Mentored developers in best practices, improving code quality and review culture
- Reduced incident response time from hours to minutes via observability initiative
- Pioneered "Toolkits" feature driving major increase in customer satisfaction
- Implemented self-service flow with Stripe payments improving product adoption
Graduate Software Engineer
Signifyd Sep 2019 – Nov 2020Fraud detection microservices
- Developed features enabling chargeback analysts to make cost-saving decisions in under a minute
- Reduced operating costs by £1000s via Elasticsearch cluster restructuring
Associate Software Engineer
Kainos Sep 2015 – Aug 2019WorkSmart SaaS automated testing system
- Led team meetings, sprint ceremonies, and product roadmap discussions
- Developed structured mentorship program for faster onboarding
- Primary contact during critical maintenance and feature releases
Skills
Languages & Frameworks
- Python
- Django
- Java
- Micronaut
- Spring
- JavaScript
- React
- HTML/CSS
AI & Data
- LLMs
- RAG
- Vector Databases
- PostgreSQL
- MySQL
- ElasticSearch
- ClickHouse
Cloud & Infrastructure
- AWS
- Azure
- Docker
- Terraform
- Kubernetes
- CDK
- Git