Clojure 2015 Year in Review

Another year, another year-in-review post. To be honest, I feel like any attempt I make to summarize what happened in the Clojure world this year is largely moot. Clojure has gotten so big, so — dare I say it? — mainstream that I can’t even begin to keep up with all the interesting things that are happening. But it’s a tradition, so I’ll stick to it. Once again, here is my incomplete, thoroughly-biased list of notable Clojurey things this year.

As I said of JVM Clojure in 2012, I think I can safely say that 2015 was the year ClojureScript grew up. It got a real release number, improved REPL support, and the ability to compile itself. But you don’t have to take my word for it: David Nolen has written his own ClojureScript Year in Review.

Clojure in the World

We already knew Clojure was being used at big companies like Walmart and Amazon. Based on public job postings, we’ve also seen places like Reuters, Capital One, and Oracle interested in Clojure developers.

Big corporations tend to be cagey about their technology choices, but Walmart’s Anthony Marcar came to Clojure/West to talk about how they do Clojure at Scale.

In other big-tech news, Facebook acquired, a Clojure startup that released an open-source library to parse structured data from text. Clojure early-adopter Prismatic pivoted away from its popular news-recommendation app to focus full-time on the A.I. business as well.

Language, Tools, and Libraries

Clojure 1.7 was released, bringing Transducers and the much-anticipated Reader Conditionals to support mixed Clojure-ClojureScript projects. Writing cross-platform libraries suddenly got easier. A bunch of popular Clojure libraries were ported to ClojureScript, including test.check, tools.reader, and my Component.

core.async got a major new release, with the added features promise-chan, offer!, and poll!.

The big news on the tooling front was the 1.0 release of Cursive, the first commercial IDE for Clojure. On the open-source side, both Light Table and CIDER got major new releases.

In the ClojureScript tooling world, Figwheel and Devcards really took off this year.

Clojars started getting financial support from the community, and CLJSJS started offering JavaScript libraries conveniently packaged for ClojureScript and the Google Closure Compiler.

Books and Docs went open-source for contributions from the community.

New books: Clojure Applied (my review), Clojure for the Brave and True in print, Living Clojure, Clojure Recipes, and many more.

Events and Community

The Clojurians Slack community rocketed from just an idea to over four thousand members. If you don’t care for Slack, the #clojure IRC channel on Freenode is still going.

The Clojure mailing list hit ten thousand members.

At Clojure/conj this year, we had the first-ever Datomic conference. You can binge-watch Clojure conference videos (Clojure/conj, EuroClojure, and Clojure/West) on the ClojureTV YouTube channel. Also check out Clojure eXchange and :clojureD.

Clojure is attracting some interest from academic computer science, including a new paper on optimizing immutable hash maps.


There’s not much more to say. Or rather, there is very much more to say than what I can capture in a single post. Clojure is here to stay. Let’s enjoy it.

Thanks to David Nolen, Alex Miller, Timothy Baldridge, Carin Meier, and Daemian Mack for their help preparing this post.

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