OSS updates July and August 2026

In this post I'll give updates about open source I worked on during July and August 2026.

To see previous OSS updates, go here.

Sponsors

I'd like to thank all the sponsors and contributors who make this work possible. Without you, the projects below would not be as mature or would not exist or be maintained at all! So a sincere thank you to everyone who contributes to the sustainability of these projects.

gratitude

Current top tier sponsors:

Open the details section for more info about sponsoring.

Sponsor info

If you want to ensure that the projects I work on are sustainably maintained, you can sponsor this work in the following ways. If you work for a company that uses my OSS, please ask your employer, that would be even better. Thank you!

Updates

In the past two months it was summertime in Europe. Due to a couple of heatwaves, it was the perfect time to spend inside and enjoy my new air conditioning, while coding ;-).

The first half of July was mostly spent on improving performance and compatibility of SCI on CLJS. SCI now JIT-compiles interpreted function bodies to JavaScript at runtime, which closes a lot of the gap with compiled ClojureScript: a tight numeric loop went from ~175ms to ~7ms, over 20 times faster than the interpreter. Implementing core protocols on custom types now also works. There's hardly anything you can't do in SCI that you can do in compiled CLJS. I released new versions of scittle and nbb that take full advantage of this.

Also in the middle of July, clj-kondo got a pretty cool enhancement. It infers types of function arguments from how they are used. E.g. when you write (defn foo [x] (inc x)) we can infer that foo is a function that takes a number. I took this principle as far as I could while preventing false positives. Of course, clj-kondo supports the latest Clojure 1.13 destructuring changes too.

In the second half of July I spent significant time on improving babashka tasks with automatic help and completions, backed by babashka.cli. You can read all about that in this blog post: Babashka tasks with automatic help and completions

In August I had the pleasure of giving a talk about Reagami at Func Prog Sweden. In the talk I gave an interactive demo of how to use Reagami in a Squint project through a REPL. I also went into detail on the algorithm that powers the fast DOM diffing. While preparing for the talk, I added SSR to Reagami too. You can view the talk on YouTube:

The last few weeks of August I created babashka.ffi, a new namespace in babashka to call C libraries. See my previous blog post: Babashka 1.13.220 gets FFI. To validate the design I wrote four libraries with it: babashka.sqlite, babashka.duckdb, babashka.postgres and filewatcher. Each one exercised a different corner of the API, along with some examples based on raylib. PacMan is particularly cool:

pac-man running in babashka through babashka.ffi and raylib

Right now I'm looking forward to giving a babashka workshop at the Clojure/conj together with Rahul Dé. We're still polishing the workshop material behind the scenes and I'm excited to see how it's turning out. I'm sure it'll be a lot of fun and hope to catch many of you there.

In between all of this, I also worked on squint. It now supports the core protocols, so you can plug in your own collections and use them with core functions. E.g. you can use Immutable.js with Squint. I'm thinking about lightweight immutable persistent data structures for squint, but so far I haven't had much need for them, outside of Advent of Code puzzles.

The above was all about making existing projects better. But I also had a few new creative ideas:

Here are some highlights per project. See each project's CHANGELOG.md for the full list.

Other projects

These are some other projects I'm involved with, but little to no activity happened in the past two months.

Click for more details

Published: 2026-09-02

Tagged: clojure oss updates

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