66 Days: Why we built a product in 1 day, part 1

Sometimes teams are capable of amazing things. We at Treeveo got the idea for a new project. So we all came into the office on 1 Saturday and built it. The project is called 66Days, it helps you to improve yourself. 

This is part 1 of a 2-part post where I talk about our social experiment called 66 Days. In this post I explain what 66 Days is and why we decided to build it. In the next part I will talk more about how we were able to build it in just 1 day.

What is 66Days?

66 Days is a web app that anonymously asks your friends about your behavior so you can improve yourself. And by improving yourself, you improve the world. How does it work? There are 4 steps:

  1. First you go to the site and decide what you want to improve about yourself.
    In my case: “I want to become more empathetic”
  2. You define the yes/no question the app needs to ask your friends.
    In my case: “Was Jeroen really interested in you the last days?”
  3. You input minimum 1 and maximum 5 friends that you think will give you their honest opinion (anonymously).
    In my case: 3 Treeveo team members, my wife and a good friend.
    66Days will ask them the yes/no questions once a week.
  4. You check your progress to see if you are actually improving, in my case: if I am becoming more empathetic. But just started a week ago, so still waiting on the first results.

66Days forces me to consciously modify my behavior with my 5 supporters, for the duration of 66 days.
There are 2 reasons why we build 66Days: we are solving a problem, and it is a fun exercise.

Why 66Days? Solving a problem

The first reason to build it was because it is solving one of my personal challenges: becoming a better me. What do you do when you want to improve your physique? You go to the gym. But what do you do when you want to improve your character?

“I want to become more empathetic”

Being an entrepreneur pushes me to the limit and exposes my strengths and weaknesses. In my case, I’ve received feedback on my character from different sources and really want to improve. For example, I wish to become calmer, more empathetic and less pushy. This isn’t something you just decide from one day to the next. You need a period of consistent practice and feedback from others. You need to select one thing to work on, and then focus on that for a period of time. Besides, you need a limited amount of selected supporters that you regularly interact with and give you honest feedback. 66Days does exactly that.

The Treeveo team liked this idea so much that we decided to build it together. We also see many potential integrations with Treeveo where leaders can improve their leadership style getting honest, anonymous feedback from their followers.

Why 66Days? The fun of the exercise

A second reason to build the app was in building the app itself. Firstly, I hadn’t touched programming code for a while and I wanted to program again so I could keep up-to-speed. So 66Days allowed me to code again (although I remain a newbie compared to Paulo and Guillermo) and design a product, writing the copy etc (although my copy writing is nowhere near Adam‘s). Secondly, 66Days is also teaching us a lot and allows us to experiment. We can now run experiments before we release them on Treeveo. Already we are running Facebook campaigns and deep analytics. Finally, it was just a really fun thing to do, to come into the office on a Saturday, work together, eat pizza and see the product slowly come to life over the course of a number of hours. We built it on a Saturday and put it live on a Monday. But the feeling I had after this one day of developing together and actually ending with a working product still gives me Goosebumps. We have such an amazing team, such a pool of talent. I now feel we can do anything with this little group of talented people.

For the moment 66Days is an experiment that we use internally. We have no business model, no marketing strategy, and we are not investing any money. Perhaps we will come in another day to develop a mobile app. But for now it exists just because we want it to … and because we could do it.

The name

People always ask me how we came up with the name. There is a study done by Phillippa Lally, psychology researcher at University College London, published in the European Journal of Social Psychology on the development of new habits. They interviewed people on how they were able to incorporate new habits in their daily life. The result was that it takes on average 66 days to develop a new habit and make it part of your life. That’s why we called our experiment: 66Days. The research even showed if you keep working on your habit, you can improve yourself regardless of whether or not you mess up in the middle of the 66 days.


So if you want to improve yourself, head to www.66days.io and create your first “streak”.

Because improving the world starts by improving yourself



Lally, P., van Jaarsveld, C. H. M., Potts, H. W. W. and Wardle, J. (2010), How are habits formed: Modelling habit formation in the real world. Eur. J. Soc. Psychol., 40: 998–1009. doi: 10.1002/ejsp.674, (http://onlinelibrary.wiley.com/doi/10.1002/ejsp.674/abstract )