Clojure 1.12.0 is now available

Original Article ↗ Hacker News Discussion ↗

Ecosystem Health & Popularity

  • Many describe Clojure as stable but niche: not growing fast, but not collapsing either.
  • Some see a shrinking or stagnant user base, especially compared to Scala, Kotlin, Go, Python, etc.
  • Others argue “lindy” longevity: code from a decade ago still runs, and they expect Clojure to still be around in 10 years.
  • Job market is perceived as small; one commenter cites low LinkedIn hits for Clojure vs Scala.

Libraries, Maintenance, and JVM Interop

  • Frequent theme: Clojure libs often look “abandoned” but are actually finished; the language’s stability means little churn is required.
  • Counterpoint: some important libs were abandoned or stalled (e.g., Android, data access, Om, core.logic, ClojureQL), creating risk.
  • Community efforts like Clojurists Together and clj-commons exist to revive/maintain popular libraries.
  • JVM interop is repeatedly cited as a major advantage and safety net when Clojure-specific libs are missing.

Clojure 1.12.0 Features

  • Big praise for add-libs and sync-deps: easier repl-based experimentation, single-file demos, and sharing reproducible snippets.
  • New functional interface coercion is seen as a major win for Java interop, removing many adapter macros.
  • Some note this release is larger than usual; others trust the core team’s conservative design ethos.

Spec, Malli, and Validation

  • clojure.spec is still used; a “spec2” successor has done work but is currently stalled.
  • Malli is praised as what spec “should have been,” but it cannot integrate with compiler macro checking because the compiler special-cases spec.

Use Cases & Companies

  • Reported uses: backend/“enterprise” systems, finance/banking, data processing, frontend via ClojureScript, scripting via Babashka, even full businesses with small teams.
  • Several notable companies are said to use Clojure heavily (e.g., Nubank, cloud providers).

Developer Experience & REPL Culture

  • Strong emphasis on REPL-driven development; Clojure’s REPL is described as much closer to Common Lisp’s than Java’s or JavaScript’s.
  • AI tools are suggested as accelerators for onboarding devs who struggle initially to read Lisp syntax.

Adoption in Organizations

  • Mixed advice: some advocate piloting Clojure on small, low-risk services and investing in training; others strongly warn against introducing a niche language into a non-Lisp culture due to hiring and maintainability risks.
  • Experiences vary from highly successful org-wide migrations to “dumped Clojure for Go” due to performance/startup constraints (especially in serverless/lambda contexts).