PaperHive Conversations: John Hammersley

John Hammersley & PaperHive

John Hammersley has always been fascinated by science, space, exploration and technology. After completing a PhD in Mathematical Physics at Durham University in 2008, he went on to help design and build the world’s first driverless taxi system now operating at London’s Heathrow Airport. John is now making it easier for scientists to collaborate and publish online as CEO and co-founder of Overleaf, the rapidly growing online collaborative writing and reviewing tool now with over 400,000 users worldwide. John was named as one of The Bookseller’s Rising Stars of 2015, is a mentor and alumni of the Bethnal Green Ventures startup accelerator in London, and in his spare time dances (and occasionally teaches) West Coast Swing!

John, thank you for coming on board as an adviser to PaperHive! Before starting Overleaf with your cofounder John Lees-Miller you did a PhD in mathematics at the University of Durham. What was your field of research and what were the biggest challenges you encountered during your studies?

Thanks, it’s great to be on board!

At Durham I studied the holographic principle, also known as the AdS / CFT correspondence, which considers in what circumstances the information in a particular (theoretical) universe can be encoded in a theory of fewer dimensions — like how a hologram takes a set of 2D information and uses it to display a 3D visualization of an object. The holographic principle is a property of string theories, and so “I worked on string theory” is my usual short answer 🙂

I think my biggest challenge (towards the end) was figuring out what direction to go in. There were so many papers appearing on the arXiv every day (on topics related to my research) that I couldn’t decide what to focus on, and I couldn’t see how I could really make a difference in my field. With hindsight, I can see that this is because I hadn’t given it long enough – I wanted to be able to see my work having an impact immediately.

This was one thing that attracted me to working in an industry at the cutting edge of science & technology (which turned out to be driverless cars) – not only would I still be doing research, but I’d be able to see the benefits of, and get feedback from, our real-world implementations (such as the Heathrow Pod) almost immediately.

The life of an entrepreneur is quite different from the life of a researcher. What do you miss from your time in academia?

For me, I found there to be a lot more day-to-day pressure in industry than I experienced in academia, and more of a focus on the end goal than on the journey.

When I was in academia, it felt like there was more leeway (at least in my field of mathematics / high-energy physics) to explore and shift focus — provided I could still write it up into a paper at the end of course 😉

Whilst I miss some of this freedom, I enjoy the way we’ve been able to develop Overleaf so rapidly over the past few years, and I’m fortunate that I’m building a company that is still very much connected to research and academia. I hadn’t appreciated the transitions would be so one-way though; I thought it would be easy to get back into academia if I wanted to, after ‘temporarily’ moving into industry, but this is actually much less likely than you might think (you can read more of my thoughts on this on my Reddit AMA and my follow up blog post).

What were the two business and product decisions that helped make Overleaf such a great success story?


On the business side, the guidance and mentoring we got from joining Bethnal Green Ventures helped turn our project into a business; we learnt a lot in a very short space of time, and it was crucial in us going on to raise subsequent investment rounds. Looking back at our BGV Demo Day pitch (from September 2013), it’s amazing when I think about how different that final version was from our first practice — they helped us make a lot of iterations!

On the product side, we kept it simple at the start, and have added features sparingly; we were lucky to get a lot of early traction, and the feedback from those early users helped guide the development of the product. It also helped us avoid developing things without an outside perspective; we were building a tool that people really wanted to use, and so they’d tell us when they hit a bug or if there was something that would make their lives easier.

With Overleaf’s over 400,000 users, you are one the most successful entrepreneurs in research communication. Please, share one “do” and one “don’t” for people considering to start a new venture.

Do seek feedback from others before you start, ideally from people outside your close friends and family, and focus the building of your MVP so that it can get you this feedback on your key features / value proposition.

Don’t underestimate the importance of being in the right place at the right time; lucky breaks are hard to come by, and even more so if you spend all your time head down on the product. Finances permitting, aim to go to (at least) one event each month. If you really don’t like networking, find a co-founder who does!

John Hammersley and his daughter

John Hammersley and his daughter

Having a family and being an eager dancer – is it possible to be a successful entrepreneur without having to work 80-hour-weeks?

I think you always find the time for the things you care about, and to be successful as an entrepreneur you need to care about your startup, and put in the time and effort it needs in order to grow.

That’s why it’s so important to start out with the right co-founder — someone you trust, and whom you have confidence in.

Dancing has had to take a bit of a backseat since Overleaf has taken off and Julia (my daughter) was born, but that’s ok — I’d be worried if I was prioritizing dancing over either my company or my daughter!

A book or article on PaperHive you would recommend?

If you’re already familiar with the AdS/CFT correspondence, I recommend taking a look at The Fluid/Gravity Correspondence: a new perspective on the Membrane Paradigm, by my PhD supervisor, Veronika Hubeny (or any of her other papers!)

About the Author

Lisa Matthias
Studies North American Studies at Freie Universität Berlin. Her research interests are Media Studies, Political Communication, and US Foreign Policy.