Nubank Building Blog
building.nubank.com.br · Company blog · on HN since 2020
Nubank's engineering blog covers its Clojure and Datomic work, Cognitect acquisition, testing, incident handling, and engineering workflows.
What HN saysHN commenters link it for the Cognitect acquisition and Rich Hickey's time at Nubank, and for its Clojure functional programming write-up.
20HN people shared it
9linked it in comments
11stories submitted
597story points
2 years agolast shared
2020people per year2026
Most-shared posts
- 1Nubank and Cognitect are joining forces5 people · 3 points · first shared 2020 · discussion on HN
- 2Clojure 15th Anniversary: A Retrospective2 people · 173 points · first shared 2022 · 96 comments on HN
- 3The value of canonicity (2020)2 people · 85 points · first shared 2021 · 71 comments on HN
- 4Rich Hickey is retiring from Nubank2 people · 50 points · first shared 2023 · 2 comments on HN
- 5We killed our end-to-end test suite1 people · 274 points · first shared 2021 · 260 comments on HN
- 6Cognitect, creator of Clojure and Datomic, is now part of Nubank1 people · 7 points · first shared 2020 · discussion on HN
- 7Enhancing engineering workflows with AI: a real-world experience1 people · 4 points · first shared 2025 · discussion on HN
- 8How we deal with technical incidents1 people · 1 points · first shared 2021 · discussion on HN
- 9Working with clojure at nubank1 people · first shared 2023
- 10Nubank acquires us company cognitect the team behind clojure and datomic1 people · first shared 2025
- 11Functional programming with clojure1 people · first shared 2024
- 12Scaling with flutter1 people · first shared 2021
- 13Nubank office pinheiros1 people · first shared 2023
- 14);1 people · first shared 2024
What HN people wrote when they linked it
puredanger · 2024-05-16
Ed's post when Cognitect joined Nubank is still a great read: https://building.nubank.com.br/welcoming-cognitect-nubank/
owebmaster · 2025-04-08
A fun fact, one of the biggest PIX players is also the company that acquired Cognitec¹, the company behind Clojure and Datomic. Until not long ago, Rich Hickey was part of the staff².
1. https://building.nubank.com.br/pt-br/nubank-acquires-us-company-cognit…
2. https://building.nubank.com.br/clojures-journey-at-nubank-a-look-into-…
hlship · 2024-05-22
Nubank purchased Cognitect (the consulting company behind Clojure) in 2020, as well as Platformatec (employers of Jose Valim); the latter was for access to Platformatec's project management expertise (see https://building.nubank.com.br/tech-perspectives-behind-nubanks-first-… there is no Elixir code running at Nubank AFAIK.
There is Python on the "other side" of the ETL pipeline, but everything user-facing is (again AFAIK) Clojure on the backend and TypeScript in the Android and iOS apps.
lbrito · 2023-08-08
>I don’t "think" anything
Yup, won't disagree with you on that one.
>which is exactly what is stated on their website.
Really? Curious to see where they say that. Let's try ddg: https://duckduckgo.com/?q=where+are+nubank+tech+hubs&t=canonical&a… the first result is:
>Get to know Nubank’s main headquarters in Pinheiros, Sao Paulo/Brazil
https://building.nubank.com.br/nubank-office-pinheiros/
Maybe their About page:
>We have offices or technology hubs in six countries, and our staff is composed of around 8,000 Nubankers from over 50 different nationalities (as of December 2022).
https://international.nubank.com.br/about/
Okay, I give up.
chubot · 2023-08-04
FWIW the original announcements in 2020:
https://cognitect.com/blog/2020/07/23/Cognitect-Joins-Nubank
https://news.ycombinator.com/item?id=23926407
https://building.nubank.com.br/welcoming-cognitect-nubank/
Very interesting story!
uxcolumbo · 2023-01-27
Nubank, largest fintech bank across Latin America uses Clojure extensively.
https://building.nubank.com.br/working-with-clojure-at-nubank/
rafaelferreira · 2020-07-23
Nubank’s co-founder and CTO offers his perspective: https://building.nubank.com.br/welcoming-cognitect-nubank/
tpmx · 2021-03-03
I tried the Sonos app since it looked very similar on both platforms. It's a lot smoother than my experience from a year ago. (Hard to really tell in the limited set of screens before hardware pairing.)
Edit: If the signup screen in the Grab iOS app is written in Flutter I'm very impressed. I want to believe.
Edit 2: Nubank: I only evaluated the sign-in screen(s), but it has enough animations at what seems like a very solid 60 fps on my iPhone X to convince me that Flutter on iOS is actually a real thing now. Very nice.
They write about their development effort here: https://building.nubank.com.br/scaling-with-flutter/
Edit 3: Maybe I jumped the gun here. Quote from that post: "We’re also facing hard prioritization decisions, especially in flows and screens that work very well in their current state (native Objective-C, Swift, Java, Kotlin, or React Native) for which there are no near-future update plans."