Hi, I'm Stef

Stef Lewandowski portrait
Hi, I'm Stef

Stef Lewandowski

Pronounced “Lev-un-dos-key”

Fractional CTO / software engineer / AI product maker based in the UK

I’m an experienced early-stage startup tech/product lead with a mix of overlapping skills in software development, design, and business model innovation. In short, I'm an early stage startup swiss army knife.

Throughout my career, I’ve sought to find repeatable ways to discover new opportunities, prototype and develop early-stage tech startups and scale them to have an impact on solving problems the world faces.

My main skill, and what I focus on continually improving, is being able to take the nub of an idea, test it, hone it, rapidly build a working first version and then iterate to take the idea from "zero to one".

I am currently working with AI and tech startups as a fractional CTO / lead engineer both in an advisory/leadership capacity and directly building software systems, and currently looking into applied AI in education and health.

A particularly exciting project I'm involved in is enabling the UK education sector to take advantage of generative AI to help teachers in their day-to-day work.

Most recently I helped an early-stage fintech/data startup, Translucent, to build the initial MVP, hire the team and raise $9m of seed investment.

I was part of the early team at On Deck, a San Francisco-based cohort-based learning platform for people with ambition (not to be confused with the fintech of the same name). Think a cross between an accelerator program and an MBA program and you might not be too far wrong. I supported the product engineering team as Director of Product, Platform. It was a technical product leadership role where I set up and coordinated Data, No-Code and Funnel teams. The company grew to 350 and reached a $650m valuation during my tenure.

During the Covid years I helped build Oak National Academy, a free online educational resource to help schools to continue providing education for students (see below for more on this).

I’ve instigated and led venture building and "labs" initiatives to explore business opportunities in a diverse set of industries: sustainability, finance, supply-chain, logistics, e-commerce, education, urban mobility, car sharing, data analytics, tech recruitment, culture and more.

I was co-founder of Makeshift, an early venture studio in London with the claim to fame that Product Hunt started off the back of one of our prototypes.

I've been co-founder of a handful of tech startups in various industries including media, education and publishing, both venture-backed and bootstrapped, a design studio, an online creativity community, a record label and assorted other ventures along the way.

You can read about my work history on my Linkedin profile.

Brands I’ve worked with

Channel 4
Comic Relief
Land Rover
Red Bull
Vivienne Westwood

I speak on a variety of topics: creativity, startups, innovation, experimentation, inspiring the next generation with the possibilities of technology, "sketching with code", and my personal journey aiming to create something every day.

I always aim to be useful, relatable, light-hearted, honest and inspiring. And above all, jargon-free!

If you'd like to book me, I'm represented by Speakers Corner in London.

A brilliant talk which landed so well with our audience

DBT Coalesce

Stef was great, delivered a great presentation and the audience found it very engaging. He received high praise and was a very approachable guy.


He was provocative and challenging at the same time as being positive and inspiring. He fulfilled his brief completely and was very flexible in the lead up to his keynote

Unlocking Potential
Oak National Academy

I believe that to be a well-rounded person you should have a healthy mix of work and service. You'll often find me doing projects or collaborations with non-profits, or doing some voluntary work.

Most recently, during the COVID years I helped the UK education sector respond to the needs of teachers and pupils by helping build an online learning platform, Oak National Academy for students to learn from home and in other settings when they're unable to attend school.

Our tiny tech and product team built and released the first version in a week, and scaled to support 4.5 million students per week to learn from home during the second wave of COVID. The wider team and partners produced almost a full national curriculum of video content and resources (~10,000 video lessons) across most subjects and made it all available for free (including finding a way to make it free to access on a phone) via the web.

It's since become a permanently-funded government department and has branched out into offering AI tools, and I'm consulting to help build some of them. Overall, Oak is my most remarkable "look what happened after those first lines of code" project!

Aside from Oak, I sit on the industrial advisory board of University of Birmingham School of Computer Science and I have a history of volunteering for tech-focused and social good organisations.

I've been a school governor at two schools, and was chair for three years at Heber Primary School in South London, where I learnt a lot about good governance.

I'm a Clore Fellow and am always interested in the intersection of modern technology and culture. The leadership fellowship I undertook exposed me to the needs of cultural and creative organisations and I've since been involved with several non-profits.

Through my running I have raised funds for autism charities including the National Autistic Society and Ambitious about Autism.

I occasionally write articles and essays, mostly on Medium, although you'll also find my words on Lifehacker, Quartz and elsewhere.

Here are a few of my most popular posts.

Serverless functions
Cloudflare Workers

If you were to ask me my preferred tech stack right now, I’d say some of these would be in the mix.

In the past I've worked with a wide range of languages, Ruby, PHP, .Net, C++, Java, but nowadays I've found that I'm most productive with this kind stack for the kinds of projects I work on.

I now work mostly in full-stack Typescript, with Python where there's an ML/AI component, and Bigquery or Snowflake where what I'm building involves a lot of data or well-defined data pipelines.

Photo of Stef running a half marathon

I started running as a complete beginner in September 2019 having not done really any organised exercise before. The daily walk to and from work was about it!

I used the Couch to 5k app to steadily get my stamina up, and kept going after I hit the 5k target.

Just over a year later I ran the virtual (because of Covid) London Marathon in a time of 3:52 🎉

There's a thread on Twitter that I made along the way, and I'm currently gathering all my Strava posts into a website that shows the journey from beginning to end.

If you're thinking "I could never run a marathon", I hope this shows that it might just be possible!

Along the way, I've collaborated with some excellent people and our work has won some awards!

Digital Leaders Impact Awards Oak National Academy

Tech4Good Awards Highly Commended
Oak National Academy

Clore Prize
Awesome Box

Hospital Club HClub100

Business to Arts Award: Best Creative Staff Engagement
Accenture: Festival of Ideas

Europa Finalist

Nokia Pitch 'n' Win
Go Genie

Smarta 100 Winner

White Bull "Bully" Winner

Finalist for Guardian MEGAs — Disruptive Technology

NUJ Regional Journalism Awards – Highly Commended
Help Me Investigate

Best Investigation at the Talk About Local Unawards
Help Me Investigate

Top 5 in the Observer / Courvoisier The Future 500

Webby Award
First Light Movies

Webby Award Honoree (NetArt)
Name in Lights

Webby Award Honoree
The Big Picture

Joint-winner of inaugural Guardian Innovation Awards (‘MEGA’) for Best Independent Blog
Created in Birmingham

Joint World Record holder!? (With many others) The Big Picture

Finalist for Royal Television Society Innovation Award – User Generated Content
4tips (Maverick TV)

British Council Digital Pioneer

#20 in the Birmingham Post’s Power 50

Alumnus of the Year, Birmingham University

Birmingham Creative City Awards Small Business of the Year

Birmingham Young Professional of the Year

Channel 4 Ideas Factory Creative Class Award Winner
3form / Type Records

Champion of Industry, Mustard award

O2 / Arena magazine – Shortlisted for Entrepreneur of the Year in Birmingham

Mustard Award for Best New Start-Up in Birmingham

Birmingham Creative City Award for Outstanding Innovation

Gold Award for Best Non-Profit Organisation Website – World Media Festival Hamburg
Birmingham Museums and Art Gallery website / 3form

NASTA winner - Best Title Sequence
Robots in Disguise