Jonathan Leahy
Staff Engineer at Pismo (Visa) by day.
On nights and weekends, I run an experiment: a software company staffed by AI agents.
Gyrum — an autonomous factory that plans, builds, reviews and deploys real products to the public internet. This site is one of them.
What I do
Staff Engineer at Pismo (Visa), building payments infrastructure at scale — Go microservices on Kubernetes, event-driven on AWS.
I've shipped across fintech, NHS software, and consumer products — from FoxPro through Go to AI agents. The stack keeps changing; the through-line is the same: real systems that actually ship.
Every platform I've built on has taught me where the next one hides its problems.
How I work with AI
Featured Projects
Gyrum.ai
An ongoing experiment in agent-run software — agents that plan, build, review, and deploy.
Gyrum.io
Another experiment — Kubernetes-based SaaS services, multi-tenant and self-serve from the ground up. The same dark-factory idea as the book, run as a platform.
Days Out For The Family
Find family-friendly attractions and days out across the UK — search, favourite, and discover places near you.
→ See all projects · end-to-end builds, architecture to deployment, on one page
The Rented Codebase
The blueprint is owned. The tests are the proof.
Jonathan Leahy
The Rented Codebase
The codebase is rented. The blueprint is owned. The tests are the proof.
Edition 2.0 · 30,000 words · three hours
A working paper on the AI dark factory behind Gyrum — why the code you ship is becoming a disposable instance, and why the precise specification is the only asset left.
Prefer to listen? Two synthetic hosts read the book and talk it through. Machine-generated, drawn from the book's own text.
Machine-generated overview · 16:13 · nobody in this recording is a person
Read two chapters free
obs-training
Self-directed observability training.
Runbooks, dashboards, and exercises for learning production-grade telemetry — tracing, metrics, and incident response. Live at obs-training.jonathanleahy.co.uk.
Visit obs-trainingWhat I work with
Go, TypeScript, SvelteKit, React, PostgreSQL, Docker, Kubernetes, CI/CD pipelines, and AI across the stack — with ElevenLabs for voice and Imagen for images.
The stack keeps changing; the concepts don't — it was never the syntax that mattered, it's the durable ideas underneath: