About

I have been shipping software for over twenty years, and mobile for most of the time the iPhone has existed. Usually solo or in a small team, and often walking into something that is on fire and needs immediate triage.

The basics: one of five engineers on the iOS team at Shazam, where I designed and coded the listening animations; Lead iOS Developer at Learn With Homer, where I trained the whole engineering team on Swift and led them through the company’s acquisition; sole iOS developer on River Health, a telehealth product, for several years; and CTO and product lead at Wingman, where I onshored an agency-built MVP and turned it into a product worth scaling.

I work through my own UK limited company, Charlie Robert Williams Ltd, and have done since 2014, for US and UK clients. For a long stretch of that I was represented by 10x Management, who still put work my way on a non-exclusive basis.

Teaching engineers is not a side effect

The thing I get asked to do most often, after building the product, is bring a team up to a standard. That is not accidental: I have been teaching for most of my career.

• Swift course, NewCircle (San Francisco, 2015), for client Epocrates
• Lecturer, Columbia College Chicago (2006–2010), MFA Music Composition for the Screen
• Faculty, Northwestern University School of Music (2001–2003)
• CodeFirst:Girls (2014–2015), instructor supporting university-enrolled women beginning to code, in Bath
• Creative coding workshops (2019–2025), across UK venues and at Knowle West Media Centre, Bristol, introducing artists to generative tools and interaction design
• TEDxBath (2019), How I See Music Using Code, on audiovisual performance systems

So when I say I trained Homer’s entire engineering team on Swift, that was not a one-off favour. It’s something I have longstanding experience with, and it is usually the most durable part of an engagement: the team is still there after I have gone.

The other half

I am also a composer and pianist, recording under my own name. I hold an MPhil with Distinction from the University of Cambridge’s Centre for Music and Science, and was previously a prizewinning concert pianist. I am currently building Play & See, an interactive installation that lets anyone explore a piano connected to a live visuals system, funded by Arts Council England, Bath Spa University and the Marchus Trust.

That is not a hobby I keep separate from the engineering. It is real-time graphics, sensor input and live systems that have to survive unsupervised public use, and the underlying problem is the one I have been working on the whole time: making a complex system feel obvious to someone who has never seen it before.

Earlier work in the same vein: SingSmash, a singing-controlled iOS game featured by BBC Music Magazine, Classic FM and ITV, and Jingle+, a physical-modeling shaker app with over half a million downloads. More going back to 1997 at c.harl.ie.

Getting in touch

The fastest way is email: c@harl.ie. Tell me what is stuck and I will tell you whether I am the right person for it.