Real-world Clojure: Lessons from Growing a Team and a Codebase - Assum

In the eight years that I've been at Ardoq, we grew our Clojure backend team from 2 to 20 developers, and tripled the size of the codebase. Within this period, we rewrote the backend from a java-application in a Clojure disguise into something that resembles a proper Clojure app and we migrated from MongoDB to Postgres. With this background, I'd like to talk about some topics from these eight years: * The migration. We did not choose Datomic. We've been running with Postgres now for two years. How is that serving us? * Hiring. How do we find the people we want to work with, what do we do to make them happy, and how do we onboard them into the codebase? * The codebase. We have a 150KLOC Clojure monolith with a similar amount of tests. How is it organized, and how do we ensure that quality remains as both the organization and the codebase grows. Biography Erik works as a clojure programmer at Ardoq, a Norwegian scale up in the EA-space. He’s a mainly a backend programmer, but tends to work wherever the code is bad enough. Given time he’ll eventually drift into some sort of devops role while trying to figure out how to run the current project even better. Lately, he's been lurking around open-source Clojure projects looking for easy bugs to fix. This is his way of paying back to the community. Recorded Nov 13, 2025 at Clojure/Conj 2025 in Charlotte, NC.