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It’s just more of everything-Stan Sarr (Koober)

by Alban Dumouilla

Koober is a veritable library of compressed books to take with you anywhere. By registering on Koober you can read at will hundreds of summaries of quality books at any time of the day. Koober selects the best non-fiction books and provides summaries to read in less than 30 minutes.

What’s on your pizza?

Quattro fromaggi: parmesan, gorgonzola, mozarrella, gruyère

You and the CTO job

The job hasn’t changed too much, it’s just more of everything

What’s your background ?

I come from an electrical & electronics engineering background (IG2I). I joined an association that was building drones and experimental rockets, and that’s where I started getting into coding.

I then moved to Mediane (industrial computing) where I coded in C, then to AFD.tech where I didn’t stay too long. I worked in 2 more companies in web development and mobile before starting Koober. Quite a lot of moving around!

How did you start the company?

I joined early stage, but it’s Alexandre that came up to me during a Symfony meetup to pitch me his idea. They just had been dumped by their CTO at the time and were working with 2 freelancers whose work wasn’t the cleanest. When I joined I had to restart the project from scratch.

I first built a collaborative version of Koober in Symfony, as well as an iOS app pretty quickly to get going. Users were able to submit texts and rate each other, but the content quality was quite low so we ended up pivoting to a more qualified approach when we joined NUMA.

We are now paying the authors that we thoroughly brief and check their work before publishing — we add about 10 new books per week.

How does your CTO job look like now?

A bit of dev (web/mobile), a bit of devops, a bit of marketing data analysis, a bit of data mining to figure out why a user that unsubscribes does so, etc. We’re trying to reduce the churn rate to under 5%, and that’s me working on that.

I try to stay organized through a backlog on Trello to prioritize depending on the current objectives of the company and where the fire is. There’s about 50% development, 30% marketing and the rest is random.

Has anything changed since you started?

There’s a LOT more work than there used to. I work 13 to 15h days, and handle a lot more responsibilities now that we have real users. We test everything before pushing to prod, we’re very cautious about not breaking anything. The good old days of code and push are over.

For the rest, the job hasn’t changed too much. It’s just more of everything: more devops, more attacks to counteract, more users to serve, etc.

Let’s talk about tech

We need to keep moving and upgrading now would block us

What is your tech stack and why?

  • Symfony 2 + Angular for the backend, SWIFT for iOS, Java for Android
  • Nodejs + Socket.io for the referral system that needs to be really reactive.
  • Monolog for logs, New Relic for server and apps health monitoring
  • EC2 for hosting, we will likely move to ElasticBeanStalk for scalability — we currently have an Elastic load balancer
  • For analytics, the classics: GA, Mixpanel, Intercom, Stripe…

Have you or will you have to change your stack? Why?

We might move the mobile apps to React native, now that the community is strong. We also had to add some nodeJS for workers and analytics.

We might move to Angular 2 in a future version of the site, as well as Symfony 3. There’s just no time for now, we need to keep moving and upgrading now would block us.

Have you ever faced a crisis?

Yes, the site went down a few times because of international brute-force attacks directed specifically to our IP. I had to change the elastic IP and create new instances to mitigate the attack.

We also have a bunch of failed payments on Stripe. Stripe tells us that it’s the customer’s banks’ fault, and the banks tell us it’s Stripe’s fault. We’re running in circles on this one for now.

The CTO life

I need to listen to users’ feedbacks

What’s the biggest problem you are facing right now?

Finding good developers. I see 2 or 3 of them a week, I’ve received 50 resumes, had interviews with 25 of them, but for now I haven’t found what I’m searching for. They are mostly too young or wouldn’t fit the company spirit.

I am searching for a web developer, an Android one and an iOS one.

What’s your most important responsibility?

0 bugs — I’m the guy that makes sure everything is smooth, on all platforms. I need to listen to users’ feedbacks when they tell us about issues and plan how to fix everything.

Would you change anything you did since you started?

I would have started in React-native directly for the mobile apps. But the community was small, I didn’t know where it was going. Now that Facebook actually uses it an the community is strong, I really want to switch, but we still have bugs to fix on the current apps, and not enough hands to do it!

The Koober people

Go where the passionated people are, not recruitment sites

What are you looking for in somebody you are considering to hire?

Search for people who are active in their field. It’s time consuming, but if you go where the passionated people are (for devs: github, stackoverflow, etc) instead of recruiting websites, you’ll find the passionated people you’re searching for.

We have found some really active github pushers that ended up having a law background, and they are the most motivated people I know.

If you had one hiring tip, what would it be?

For designers I directly search on Sketch or freelancers sites. For devs, directly on StackOverflow. I try to figure out the level of the guy and send him a direct message.

I usually contact the people that answer my StackOverflow questions, of if I answer them and their question was smart, etc.

Global vision

We need to be a real tech company, and that means convincing the rest of the team of this necessity

Where do you see Koober in 2 years?

We will be famous in France, and will start hitting the english market. I’m convinced England is better for us than the US to start in, as the culture is closer and we already have a competitor installed in NYC (Blinkist).

I also want Koober to become a true tech company — that’s how you scale! Better tech means quicker execution, as for now we have a lot of ideas but can’t build them as fast as we would like.

The number of mobile users will also go up a lot, so we’d have a pretty strong mobile team.

What will be the hardest problems you will have to solve to reach that point?

Becoming a tech company means convincing my team that it’s needed, because it’s expensive. The whole team’s spirit needs to shift to thinking about the product and how tech could help consistently.

Anything to add?

It’s awesome to talk like that. Techs don’t talk about their problems usually, we have some communication problems and recognition. A company rarely talks about the tech team, it’s nice to be under the spotlights!

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