The Playbook's 2024 Year In Review
The most popular and most important articles on The Payments Engineer Playbook in 2024.
Back in August, I was seriously considering whether this newsletter was worth continuing. It had less than 100 subscribers, and I had failed to struck a chord. Something was missing—something so obvious now, it pains me not to have noticed it early.
I was an amateur.
Today, The Payments Engineer Playbook is growing, strongly and steadily. I am both proud and grateful. Proud, because every Wednesday, more than a thousand subscribers receive, straight into their email, a few thousand words on the engineering of money software, written by me, and they like it. Grateful, because over 2024, I’ve received words of encouragement from people all over the globe, telling me that some article resonated with them, that they spent Thanksgiving binge reading The Playbook, or that they wanted me to keep up with the good work.
The Playbook has changed my life; I hope that, in 2024, it had at least a tiny impact on yours.
This year, The Playbook published 18 articles, all free. They all dive deep into some particular aspect of building software for the payments industry, what I call money software.
Today, I summarize the most popular and most important articles of 2024.
The 3 Most Viewed Articles
The 3 most popular articles on The Playbook according to Substack’s statistics:
66.5k reads
Both a reminiscence of my startup life and the paradox of trying to understand something in depth and in a rush, Engineers Do Not Get To Make Startup Mistakes When They Build Ledgers managed to reach the top of Hacker News and stayed there for a couple of days.
37.7k reads
Having published my first article on The Playbook a week before, Cringey, But True: How Uber Tests Payments In Production was my first big hit. Charity Majors, the author of one of the talks the article refers to, went to Twitter to give her perspective on it. It was the highlight of my summer.
5.19k reads
You’ve seen state machine diagrams already. You know what happens to them: they grow like weed. It is the complexity of transitioning from one state to another what makes payment systems especially difficult to deal with in terms of state machines. But like testing in production, avoiding state machines is heresy.
The 3 Most Important Articles
Not as popular as the articles I shared above, but in my personal opinion the must-read, the ones I struggled with the most, the ones I learned the most while writing them:
The Sagas paper is a database design from the 1980s that made its way into the distributed system world. It describes a pattern of task execution that trades atomicity for availability, and ties nicely with the idea that payments are a single flow of information that’s artificially split into a series of steps.
Naive engineers approach domains they don’t know with the concepts laid out on Domain Driven Design, one of the Big Books Of Software Engineering. Stripe engineers did that. 8 years later, they had to redesign their whole Payments API from scratch as a result.
This article, and its prequel The American Way of Building 3DS, were less popular than I thought they would be. There’s a lot of misunderstanding about how exemptions work, and a lot of SEO articles out there on the topic that are plain wrong.
Leveling up your payments engineering skills
From store credits to digital checks, engineers of money software have to get better at state-of-the-art engineering techniques as well as concrete aspects of the payments industry.
However, specific publications for payments engineers aren’t common. I dare say, The Payments Engineer Playbook is the only one out there.
More than a thousand people receive every Wednesday a deep dive on one particular aspect of their job, and read it carefully to become a more skilled and more valuable engineer of payments.
You may know that this publication will become paid in 2025. You can pledge your subscription before the price increase. Find all the information here:
I am so grateful to The Playbook’s subscribers, who keep the newsletter going. I wish all of you a Merry Christmas and a Happy New Year.
This has been The Payments Engineer Playbook. I’ll see you next week.