I entered an Ironman before I could swim
In 2021 I signed up for my first full-distance triathlon. I couldn't swim freestyle. I learned because I had a start line coming, and I've now finished five of them, along with dozens of middle-distance races and a few ultras.
I'm not a natural athlete. I have a demanding job and the same number of hours in the week as everybody else. That matters, because it's the person Aegis is built for.
I tried every way there is to train
Each one worked up to a point, and each one let me down in a different place.
Plans off the shelf
Sixteen weeks, written once, the same for everyone. Fine until I got ill, travelled for work or had a bad week. Then I either forced it or quietly stopped following it.
A one-to-one coach
It works. It also costs £2,000 to £3,000 a year, which puts it out of reach for most of the people I train with.
Coaching myself
I had the data and not enough hours. Planning my own training became a second job on top of the training itself.
How it happened
I started using AI to write and adjust my own training
My day job was building AI systems, so I pointed one at my own training. It planned the week, I told it how the week went, and it changed the next one.
Two full-distance races in three weeks, then under five hours
I finished two full-distance triathlons three weeks apart on that plan. In May 2025 I went under five hours for the middle distance, a target I'd missed for years on plans written by people.
It worked on me, so I built it properly
What I had was a prototype held together by my own knowledge of what to ask. Aegis is that idea rebuilt so it works for an athlete who doesn't know what to ask, with a coach's rules around every decision.
A 40-mile ultra, trained for on Aegis
I use it for my own racing. The plan for this one was built and adjusted by Aegis right up to race week, including the morning it eased my run after four hours of sleep.
A live product, shipping most weeks
The platform is in production with real athletes, connected to their watches, and has had more than fifty releases since December 2025.
Who I am
I've been building software for more than twenty years. I started as a developer in 2004 and spent eleven years on a platform that runs large-scale, high-stakes exams, working my way up to running the product.
Since 2016 I've been a CTO. At STRAT7 ResearchBods I set up the technology function and helped take the group from about 20 people to more than 400, through four acquisitions. At Red61 I led the move of the Edinburgh Festival Fringe's ticketing onto the cloud. At Aveni, an AI company in financial services, I was responsible for putting language models and AI agents into regulated products, and grew the team from 21 to 56 in a year.
Today I run Naylor Technology, where I work as a fractional CTO and advise growing businesses on how to adopt AI properly. My approach is AI-Forward, not AI-first: use AI to make people more effective, put rules around its judgement, and keep a record of what it decides.
I designed and built Aegis myself, on exactly those lines.
Why it's called Aegis
In Greek myth the aegis was the shield carried by Zeus and Athena. That is the job I want the product to do. A good coach pushes you, and a good coach also stops you when you're about to do something daft the week before a race.
I also train with a triathlon club and a group chat full of beginners, age-groupers and qualified coaches from around the country. Most of us keep going because of each other. The plan is only part of it, which is why clubs and community are in the roadmap alongside the coaching.
I want the person who has just entered their first race, and has no idea where to start, to have what I didn't.David Naylor
See what it became
The platform page has the detail. The others are written for athletes, coaches and investors.