Building world-class tech teams: 3 takeaways from Zehan Wang, former Head of Cortex Applied Research, Twitter

Posted: 17 December, 2021
Man talking to a group

Zehan Wang had had an exciting and fast-moving entrepreneurial journey at Entrepreneur First (‘EF’), from meeting his co-founder Rob Bishop, working together to founding Magic Pony which eventually got acquired by Twitter.

He then spent the next 5 years as a people manager at Twitter, starting from the role of engineering manager to then becoming head of the applied research group which is one of the main pillars in Twitter Cortex.

EF recently hosted an AMA session with Zehan where he unpacked his thoughts, learnings, and experiences on hiring and building strong tech teams at Magic Pony as well as Twitter.

Here are the 3 biggest learnings that we caught:


Napoleon Hill once said, ‘It is literally true that you can succeed best and quickest by helping others to succeed.’

And this was one of the steepest learning curves for Zehan during his early entrepreneurial journey, learning to let go and delegate more. 

“As a founder (and also as a manager), you are usually the fallback to everything and have to make sure it all works. And so between Rob and I, we had to cover everything from development work, accounting, legal work, and of course, hiring,” shares Zehan.

“So when we eventually hired others to take on tasks that I used to do myself, I realised that it was actually quite hard to let go, and would sometimes end up micromanaging a little, thinking that I could just do it faster myself. 

However, you need to have some patience when introducing others to new tasks, and fundamentally, there’s only one of me and I can’t be doing all of these things all at the same time. 

It requires a shift in mindset, and you should aim to not be a bottleneck and to empower the rest of the team more. This also frees up your time to deal with the other spinning plates you might need to tend to at the same time. 

And adopting principles from the Eisenhower prioritisation matrix is one of the good ways to optimise for the tasks to delegate and the things you have to do yourself.” 


It is no secret that great people build great products that get great customers and go on to build great companies. The difficulty, however, lies in the search for and assembling that capable team.

“Ultimately, hiring is all about getting the right people at the right time. In the beginning, especially, the challenge is building a company can be very fluid and you have to be adaptable to changes in future needs,” tells Zehan.

“And as a founder, you are always either hiring or selling (you can think of hiring as another form of selling).

Finding and recruiting talents isn’t easy, and it certainly helps to use all available channels from LinkedIn, existing networks, events as well as leveraging external help such as from recruiters.

That said, doing the outreach yourself can have its own merits and is more likely to get you a response from potential candidates (as opposed to recruiters who are often ignored). 

You can find candidates in the most unexpected places. For example, I happened to be into climbing, a sport where it seems a large majority of them work in tech, and one of my early hires was someone I met on the climbing wall.”

“As for the aged-old dilemma on who to hire – should you go for the experienced hire, those fresh out of universities or college, or those who are in their early careers – there’s no one answer.

You need to factor in what sort of talent contributes to the core value of your business and how easily you can find junior vs senior folks, as well as the skills / role you need to achieve your objectives.

For instance, back at Magic Pony, we were laser-focused on building a deep learning-based solution and were prepared to take time to get to product-market fit. 

And so, given that deep learning was nascent back then, we hired certain PhD graduates fresh from academia as they were a good option when it came to finding people who had hands-on experience with the family of machine learning methods we were interested in. 

While we didn’t have to compete as hard on salary, we offered them a good amount of equity and it was still crucial we sell them on Magic Pony’s mission and an opportunity to put years of research knowledge into building new, practical solutions. 

Twitter, on the other hand, was a lot more complex – they had built up a solid reputation when it came to web/mobile technologies, but did not have a very strong reputation when it came to machine learning. 

Candidates would also have higher expectations of what they got out of working at a large tech company versus a new startup. Beyond just pay, we had to consider career prospects whilst also conforming with standards around career ladders, levelling of roles, as well as pay bands across the company.

There is no magic bullet. The stage your company is at and what your company effectively does should form the bedrock of your hiring strategy, but you should look at hiring as a key way to add value to your company and not just people to do jobs.”


Simon Sinek’s book titled, Leaders Eat Last, brings home the point of true leadership – it isn’t just about managing numbers, it also involves helping people thrive and find meaning in their work.

“Structuring a win-win deal with your team is paramount. Yes, they are here to solve your business needs, but they are also humans; they have their own ambitions, dreams, and goals too,” says Zehan. 

“If they can consider working with you as more than just a job, they will also become strong supporters and advocates, sticking with you through both the ups and the downs. Invest in them and they will be the ones who will carry your company to the next stage of growth. 

You have got to think about what sort of difference you are making in their lives and how their roles are going to grow over time. If you hire someone junior, consider who would be mentoring them and helping them grow. If it’s someone senior, consider how you can empower them to take on more as well as help with growing the team further.

Another way to look at hiring and growing people is to consider how they can become your successor to specific roles you have been doing. Consider how this enables you to operate at a greater scale and for the company to grow further / faster.

That really helped me lead and build teams. At Magic Pony, we grew to a team of 14 before getting acquired by Twitter.

And at Twitter, the Applied Research organisation I was leading grew to 50 people by the time I left. This was partly enabled by one of the original team members of Magic Pony who I mentored and helped progress in his role at Twitter from senior researcher to senior manager. They in turn led their own team and grew it to 15 people, which hugely contributes to the growth of the overall organisation.”

From hiring strategies to compassionate leadership, Zehan showed that there’s plenty to navigate to build strong tech teams and more to learn. For those interested, he would recommend reading Managing Humans by Michael Lopp, a very useful resource on how to build a sustainable and useful engineering culture. 

Zehan’s final piece of advice for managers and leaders is to keep an open mind and stay committed to placing people at the centre of your leadership. 

If you’re keen to learn more about early-stage company building, you may be interested to see how other EF portfolio companies have done it. nPlan’s CTO Alan Mosca shares how they designed their company culture around three key values and  Phantasma Lab’s CTO Maria Meier believes in designing a diverse company from the ground up