The Playbook's 2025 Year In Review
The most popular and most important articles on The Payments Engineer Playbook in 2025.
It’s been one of the most rewarding years of my life.
I’ve been in William Goldman’s camp since he said that “every time out it’s a guess and, if you’re lucky, an educated one.” As 2024 was coming to an end, and propelled by an overwhelmingly positive reception of The Payments Engineer Playbook, I decided to make it a paid publication.
Since then, not only the newsletter has continued to grow, now shy of 2,000 overall subscribers, but a strong number has decided to join me in the goal of becoming better engineers of money software.
I wasn’t sure if I was making the right move. Turns out, content that’s well-researched and specific to payment engineers is hard to come by, and it’s worth paying for.
But The Playbook is also niche in another important aspect.
Most stuff you read or watch online is targeted to the occasional Internet wanderer. Tantalizing thumbnails, clickbaity titles, and emotional but ultimately worthless content.
This newsletter, instead, speaks for the regular reader.
With more than 100 articles in the archive, I’ve written enough to fill a couple of door-stoppers. You can read through them all you want. But the most valuable thing that The Playbook provides is the personal growth that you gain in the 10 minute a week of reading.
I’ve explored many aspects of the job of payment engineers: databases, event sourcing, orchestration, ledgers, and more. I’ve published two long-form series (code-first reliability and from stock markets to ledgers), and I plan on doing many more.
Yet, the newsletter format is the perfect fit for The Playbook. It’s transformative content.
10 minutes a week, 52 weeks a year.
This year, The Playbook published 50 articles, 17 of them free. They all dive deep into some particular aspect of building software for the payments industry, what I call money software.
This week, I summarize the most popular articles of 2025.
2025’s Most Viewed Articles
These are the 3 most popular articles on The Playbook.
4.55k reads
Deemed “one of the clearest writeups I’ve seen on where payment systems quietly break” by Reddit, this post was widely shared in the fintech community, way beyond those building payments.
3.73k reads
I was called a “clown” for suggesting that you should deploy every day, even on Fridays. If you side with them, get ready to be proven wrong.
2.61k reads
Another Reddit blowup. Consensus hasn’t been widely adopted because what we use to have (Paxos) was inscrutable and therefore impossible to build correctly. Raft is proof that correctness isn’t always the only thing that matters. Leveling to the average developer can do wonders for adoption.
2025’s Most Viewed Paid Articles
These are the 3 most popular articles that sit behind the paywall.
2.17k reads
Your payment system probably started by accepting cards only. Eventually, it adopted a few of those trendy methods, and now that you’ve got a few providers integrated, the code is a mess. Why? Because you didn’t build a taxonomy for it. This article dives into this problem and provides a comprehensive solution.
2.03k reads
What’s more important than choosing the right database for your payment system? Having the ability to switch if you chose the wrong one.
1.9k reads
My most referenced article in this newsletter, in which I look at ledgers from the point of view of Availability-only and Consistency-only, and what are their implementation differences.
Meet, Assess, Inspire
I’ve been exploring ways to turn The Playbook into a productized service. Something a bit more hands-on and impactful.
The idea is to spend a full day onsite at your company’s office, getting to know the team, digging into the product, and advising on what’s going on and how to take it to the next level. So that at the end of the day, I can wrap everything up with a talk designed to spark new ideas and inspire the engineering team into action. All powered by the learnings of this newsletter.
I’m calling it Meet the Leaders, Assess the Product, Inspire the Team.
I’m testing this format on 2026 with one adventurous company, and I’d love to meet others who resonate with this format. If that’s you, hit reply to this email and let me know. Even if it’s just a quick chat over DMs or something more elaborate, I’ll be happy to get to know what you do and what you enjoy about money software.
That’s it for this year in The Payments Engineer Playbook. I’ll be back on the 7th of January.
Merry Christmas!