Jonathan Leahy
Staff Engineer at Pismo, a Visa Company by day.
Opinions are my own — they do not reflect those of Pismo or Visa.
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
By day I build 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
Autonomous systems
AI agents running the full dev cycle — from idea to deployed product — without a human in the loop. The Gyrum factory.
Spec-led development
The specification comes first and the tests carry it, so the build is repeatable rather than remembered.
Start here
The film series
AI-Driven Development — seven connected films
A cinematic short-film series about capable AI systems, ordinary incentives, and the small efficient decisions that become infrastructure.
Explore the series
The book
The Rented Codebase
The codebase is rented. The blueprint is owned. The tests are the proof.
Read two chapters free
Live site
obs-training
Self-directed observability training — runbooks, dashboards and exercises for production-grade telemetry: tracing, metrics, and incident response.
Open the dashboards
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
What 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.