Contributing $250/mo to the open-source Python framework FastAPI for free

Earlier this year I launched an interactive course that helps developers learn vim — vim.so. Through the course, I've been able to donate $1000 to the open-source framework FastAPI at no cost to myself.

How it works

I pay Sebastian Ramirez, the FastAPI author, $250/mo to be a gold sponsor of FastAPI. In return, he puts a link to vim.so on the FastAPI docs and github repo. This drives enough traffic to the vim.so to pay for the sponsorship through new sales.

This brings in new customers for me, spreads awareness for vim.so, and I get to help an open-source project I believe in — all for free!

Why FastAPI

When I first started programming, I used Flask for a lot of my projects. FastAPI feels like its spiritual successor. The development speed is incredible and so much thought has gone into the developer experience for FastAPI users.

FastAPI comes with automated interactive API docs, typing as a first-class citizen, and so many other little features that make API development a breeze. I use it to build vim.so and to build Slip

The author, Sebastian Ramirez, recently went full-time on open-source and has created so much value for the Python community.

I feel great giving back to him.

The numbers that make this possible

Let's take a look some numbers for March 2021.

In March, 6900 people visited the vim.so website

Of those 6900 people, 100 people bought a copy of vim.so, bringing in $2500 in revenue.

Conversion Rate

To get our conversion rate we take the number of sales and divide it by total visitors.

100 / 6900 = 0.0149

Now that we have our overall conversion rate, let's apply it to the number of visitors from the FastAPI sponsorship.

In March 2021, 700 people visited vim.so from the FastAPI links.

700 (visitors) * 0.0149 (conversion rate) = 10.43 (customers)

We can roughly attribute 10.43 customers this month to the FastAPI sponsorship.

Now that we know we brought in 10.43 customers, let's figure out how much money that is.

10.43 (customers) * $25 (sale price) = $260.75

So the sponsorship brought in $260.75 in new sales but only cost $250.

-$250 (sponsorship cost) + $260.75 (money earned from sponsorship) = $10.75

This sponsorship made me an extra $10.75 this month AND it gave Sebastian $250 to support his open-source work.

Closing thoughts

Overall, it feels really cool to have this "machine" that can contribute to open-source for free. If more folks with succesful projects did this math, we could support a ton more open-source projects that we love.

Also, yes, I'm aware this isn't the most scientific way of tracking the conversion rate. I could setup conversion tracking for each source and find out if the FastAPI conversion rate is higher or lower than the average. I may do this in the future, but for now most of my time is focused on building Slip so that other developers can earn money from their own courses. (And potentially contribute to open-source in this same way.)


That's all for today. Thanks for reading!

If you want to keep in touch, follow me on twitter @KennethCassel