Here's the initial version of cljbang, a small but powerful emacs package that lets you use Clojure syntax, EDN and a part of the stdlib in .clj files. It's all running on Elisp, there is no transpiler process running externally. In the Squint-tradition, it tries to stay close to the host and let the host do the heavy lifting for us.

Thank everyone who tested Datalevin, reported issues, contributed code, shared benchmarks, trusted it in production, or simply asked hard questions.

Clojure 1.13.0-alpha5 is now available!

Java 17 baseline

As of this release, Clojure requires a minimum Java 17 runtime and compiles to Java 17 bytecode.

• CLJ-2872 Move to new ASM and emit Java 17 bytecode
• CLJ-2383 Add new java.lang classes to automatic imports
• CLJ-2892 Remove uses of Java’s security manager, which is going away
• CLJ-2920 Javadoc support updated for Java 17+

Other changes since last alpha

• CLJ-2968 Qualified :keys bindings in destructuring can only be unqualified symbols (regression fix)
• CLJ-2969 Add :select base cases to tests
• CLJ-2897 prepl is missing DynamicClassLoader and *repl* binding from repl

SCI (Small Clojure Interpreter) is now JIT compiled on CLJS by default. This means that performance is close to native compiled CLJS when using loops, etc.

Before:

(js/alert (with-out-str (time (loop [i 0 j 1000000] (if (zero? j) i (recur (inc i) (dec j)))))))

This would show around 40-50ms in your browser, but now only shows 3-4ms, which is as fast as it can reasonably get. (Numbers may vary but a 10x-20x speedup is typically what you see).

So say goodbye to numerical hot-loop issues in SCI if you were using it for any animations and couldn't get to 60 FPS or stuff like that. As long as your page supports js/eval, it'll be fast (or if it isn't let me know and we'll fix it). If your page does not support js/eval, e.g. when using Epupp on a page that doesn't allow it, SCI falls back to interpretation, so you can still hack the page to your likings ;).

Both nbb, joyride, scittle and epupp have all been updated with the new version of SCI.

Error messages/locations have all been preserved so it doesn't work in any other way than it did previously, it's just a drop-in upgrade.

More information: https://github.com/babashka/sci#jit-compilation-in-clojurescript

Project is actively developing, so for now only basic Excel, but looks like it covers big part of Excel usage nowadays.

https://saltrim.michelada.uno

Feedbacks are welcome!

CIDER 2.0 ("Terceira") is out! 🎉

Fourteen years after nrepl.el 0.1, this is easily the biggest CIDER release in ages - not because of shiny new features, but because most of the important existing ones got a careful overhaul: transient menus everywhere, inline macro stepping, rich (content-type) results on by default, call-graph browsers, and a seriously polished debugging toolbox. The docs were restructured as well, so finding things should be much easier now.

Release notes: https://github.com/clojure-emacs/cider/releases/tag/v2.0.0

Release announcement blog post: https://metaredux.com/posts/2026/07/15/cider-2-0.html

Go play with it and let me know how it feels - and remember, the best is always yet to come! In the REPL we trust!

Get the graph back from your DevOps tool. Implement the graph in Clojure and add Aspect-oriented programming to it. I think this is the only reasonable way to do DevOps. Everything else is ticking bomb waiting to explode.

https://github.com/amiorin/green

Go check out the talks and see what’s coming this year: https://2026.clojure-conj.org/schedule

Also, a nice bonus: Stuart Halloway will be giving the closing keynote.

Clojure 1.13.0-alpha4 is now available!

Destructuring changes and additions

Idents after & in :keys!/syms!/strs!/:keys/syms/strs must now be actual keys, not binding symbols. This is a change in syntax since alpha3. Note that symbol keys should be quoted as unadorned symbols are binding symbols.

:or now accepts key→val mappings in addition to binding→val.

Added a new :defaults name directive at top level to bind name to a map of defaults, key→val. Binding symbols in the :or map are transformed to the key value in the :defaults map. :defaults without :or is an error.

:select name, introduced in alpha3, now selects deeply, through nested maps, and fills in values for missing keys from :or. The :select map contains all keys mentioned anywhere in the binding form.

• CLJ-2964 :select directive in map destructuring
• CLJ-2966 :defaults directive in map destructuring
• CLJ-2967 tests for nested destructuring

Other changes since Clojure 1.13.0-alpha3

• Added `clojure.core/some-vals`, a predicative filter of nil map values
• CLJ-2870 Exception phase during top-level eval is miscategorized

Does Clojure/Script Compiler have a roadmap similar to https://rust-lang.github.io/rust-project-goals/2026/roadmaps.html

What are the next big features the language is targeting?

:select directive in map destructuring

The :select directive binds a name to a subset of the map being destructured containing only the keys mentioned (anywhere) in the binding form.

• CLJ-2964 :select directive in map destructuring
• CLJ-2963 Update specs for :select in destructuring

Other changes since Clojure 1.13.0-alpha2

• RT.map, and thus reader, tracks new PAM thresholds
• CLJ-1789 select-keys - improve performance (transients, etc)
• CLJ-2958 ILookup on sets
• CLJ-2902 pprint - prints arbitary objects in unreadable form
• CLJ-2801 TaggedLiteral - doesn’t define print-dup
• CLJ-2269 definterface - does not resolve parameter type hints
• CLJ-2781 clojure.test/report - docstring has broken references
• CLJ-2929 zipper - docstring typo
• CLJ-2901 bytes, shorts, chars - docstring typos
• CLJ-2811 scalb - docstring links to the documentation for nextDown
• CLJ-2809 clojure.math/floor - docstring has line that should be on ceil docstring

Not the original author. Sharing because I found it interesting. Especially the point about clojure-lsp which I have not seen anyone say before.

Reg. Clojurescript, while it still has a lot of merits, does Squint offer a better path nowadays for the interop pain points mentioned by the author? It now has a browser repl and has had some nice additions recently. Is anyone using it in production for serious apps?

Thanks To Clojure Community, I am Abe to build stuff I like https://youtu.be/uGu7vNhQCDE

Release notes: https://github.com/babashka/sci/blob/master/CHANGELOG.md#01454

Have fun making a scriptable mobile Flutter app!