State of Clojure Survey 2016 Analysis

The State of Clojure 2016 survey results have just been published. Last year I wrote an summary of the free text comment portion of the State of Clojure 2015 Survey. I enjoyed writing it, and it was my second most popular post of the year, so I’m repeating the process again.

In his summary, Justin said that 62% of the responses were positive. That number sounded low to me (but was presumably calculated by SurveyMonkey). I would have estimated closer to 80% after reading through them all. A little under one quarter of the 2420 survey respondents left a comment.

I’m reusing most of the same categories from last year so interested readers can compare with last years post. Some comments have been lightly edited for spelling, clarity, brevity, and niceness.

Error messages

Error messages were the biggest pain point for people last year. This year there were still many complaints about error messages and stack traces, but a lot of people are waiting to see what spec brings. There was a lot of discussion about spec error messages several months ago, but it seems to have gone quiet. I’m really hopeful that spec will improve error messages.

This year Figwheel has started providing very sophisticated reporting of compile errors, and configuration problems. It has made a massive difference to my ClojureScript workflow. Thanks Bruce!

Please Please Please can we get better error messages. …

ClojureScript has come a long way, but I still encounter errors that are totally perplexing. Better debugging would help enormously.

Error messages are very frustrating and it is hard to find where the error occurred and why. Errors coming from underlying Java code are only somehow relevant to the Clojure that produced them. Programming with dynamically typed language rocks when inferred types align with your idea, but when it’s not, things get fuzzy.

Please, please, please, please, improve error messages. This would single handedly improve: new user onboarding, community feedback (let’s admit it - it is a small community), rapid iterations, usage of the REPL, usage of spec and testing, and other areas. …

I consistently see error messages being the biggest barrier for learners of Clojure, and even more so for ClojureScript

I think a concerted focus on improving Clojure’s error reporting & handling would benefit both newcomers to the language and experienced developers alike and would result in considerably less wasted time & effort.


Last year had just been revamped and open sourced. I wrote at the time:

I have high hopes that it will become a central source for high quality, official documentation and ease the pain for newcomers. has had some contributions from the community, but it still doesn’t have the breadth of material needed to be a central source. I would love to see something like Python’s web documentation for Clojure. Renzo Borgatti is writing a mammoth book “The Clojure Standard Library” which will cover the entire Clojure standard library.

… Please improve the documentation. Recently I heard someone describe Clojure documentation as “comically terse”.

A simple way to get someone up and running that is a standard for the community would be great. There is nothing more frustrating than telling new people to “Google” for a solution and pick one you like… They never get further than reading the docs.

Clojure appeared to be a nice language when I started with it and I do not regret this decision. The flip side is that I had hoped that the poor documentation would have gone away by now – 1.4 was the first version I used and it does not seem to have improved. That’s a shame. Documentation helps new users and really, hinders nobody.

Clojure docs are too terse. They assume that the reader already fully understands the concepts being described, and merely needs a refresher. …

Clojure’s community is surprisingly small given it’s output. This leaves documentation and tutorials sparse because they require time and effort that is in short supply. …

I think both and could use a better “Get Started” experience. It’s our best opportunity at a first impression but we rely too heavily on third party docs. For example, on the reference section starts with compiler options. Doesn’t really capture the imagination.


Again, Figwheel has been leading the way in improving tooling on the ClojureScript side. Tooling is still a pain point, but seems to be less so than in previous years. For Clojure editors, Cider, Cursive, and vim-fireplace are all used pretty much the same amount as last year, but Atom has entered fourth place, presumably coupled with proto-repl.

One thing we’re used to from C#/Java that would be awesome to have is a better unit testing framework with IDE integration. …

The build toolchain for cljs has been a pain. All of my learning has come from cloning public repos and seeing how they do it.

A huge thanks to the community for invaluable tools like Leiningen, Parinfer and the various IDE plugins like ProtoREPL or Cursive. And of course huge thanks to the core team for excellent stewardship of Clojure itself.

While tooling for Clojure is improving there needs to be a lot more resources devoted to it. I am currently in a Java shop and the only realistic option is Cursive.

Startup time

Startup time was another persistent complaints this year. Unfortunately there wasn’t always enough information about whether startup time was a problem in development or production. There are several good options for avoiding constantly restarting Clojure REPLs in development (and in production), but perhaps for newcomers these are too complicated to setup, or they don’t know about them?

Love Clojure … hate its startup time!

Love the language and will keep at it. Primary frustration is with the start up time and tooling. In particular, I’m finding it difficult to quickly test the backend and frontend of my application with Boot.

… We love functional programming, but hate Clojure’s long startup times. We do what we can to minimize this (using test-refresh, REPLs, etc.), but it is still very painful, and we find ourselves twiddling our thumbs waiting for a restart several times a day. Similarly, our Clojurescript compiles take ~60 seconds (:simple optimizations) or ~30 seconds (:none optimizations). This slows us down substantially. Coming from Python, where compile and startup times are sub-second, this is the biggest complaint from our team.

Clojure would be perfect with faster startup time and a little less memory usage. Seriously I don’t even mind the java stack traces.

REPL startup time is all I care about. I use emacs+cider, and it takes an age. Otherwise, I am completely happy with Clojure :)


Justin specifically mentioned marketing and adoption as a common theme amongst the feedback:

One relatively stronger theme this year was the need for better marketing for the purposes of expanding or introducing Clojure within organizations, which is a great area for contribution from the entire community.

In my opinion, one of the areas where Clojure could improve on marketing is on the main Clojure and ClojureScript websites. I think Scala in particular has done a really good job of this. Elm and Rust also do really well in presenting the main reasons why you would want to use their languages. The community isn’t able to help with this, as contributions to style and templates are not currently wanted.

Last year I mentioned Cognitect’s case studies on Clojure adoption, this year Juxt has done some great work with their case studies of companies using Clojure in Europe.

Anecdotally, I’ve seen fewer people coming along to the Auckland Clojure Meetup than in previous years, although we’re working on a fairly small sample size. I’m not sure what (if anything) to make of that.

I would do 100% of my development in Clojure if the enterprise-y company I worked for allowed it. “Reason for not using Clojure as much as you would like”? Management not on board.

I’d love to see more “serious” support for ClojureScript: when I present ClojureScript to colleagues, it looks like a thing supported by several enthusiasts rather than a platform supported by a company.

Clojure is very solid. As a frontend developer, a stable build system, DCE and syntax stability are very valuable for me. I failed to convince my CTO on Clojure and instead we stuck to ES6/ES7. The main concern of management was hiring and training people. Although the learning curve for Clojure is easy, people still have a perception that LISP syntax is esoteric and difficult to pick up for someone completely new to the ecosystem. This myth has to be busted on a larger scale.

Language is great, community is great, the “marketing” is not that great. You guys have a great language and you are struggling to sell it.

[I] would love to see better marketing from Cognitect and other Clojure centric shops. Selling Clojure to a Java shop is not easy. It can and should be easier. (and simple, but I’ll take “easier” here first)

As an average developer fluent in Java, I would love to use Clojure more, but the biggest hurdle for me is the lack of peers interested in Clojure. At the local meetup people report the same situation at their organisations. Pity, because Clojure is super cool! Thank you.

Love Clojure, really. Can’t convince my peers that it’s worth investing the time to learn it though.

The Clojure community needs a “Rails killer,” and only Arachne holds serious promise for that.

Clojure/ClojureScript ecosystem could benefit from stronger stewardship from Cognitect to propel it into the mainstream with a focus on a killer app or a industry domain similar to the way Light Bend has been focusing on enterprise and reactive system to promote the Scala ecosystem. …

I’m in Shanghai and we barely have full-time Clojure developers in China. We formed online groups, but I guess we need help to push it to the next level.

And the age old developer question:

How can we get management to understand what they don’t understand?

Language Development

Like last year, there are still concerns about the contribution process, and the opaque decision making process for Clojure’s development.

Engagement of community is still sub-optimal, there are talented individuals who could be engaged more and productively so without opening it up to the peanut gallery.

I wish that the core Clojure development process was more flexible and friendly. I (and all the Clojure developers I know) have pretty much given up on trying to make suggestions or tickets about Clojure because I usually wind up banging my head against the wall and getting frustrated. The core team are under no obligations to explain themselves or their motivations, but they would save a lot of frustration from new community members wishing to contribute if there was a prominent document outlining the philosophy, and what kinds of changes and suggestions are and aren’t welcome.

A more open approach to development and contributing to Clojure would be appreciated. I’d love to contribute to Clojure but the mess of a lot of the code in Clojure and the JIRA-based contribution model is a barrier. I know that’s what Rich likes and see the rest of Cognitect are happy contributing in this way but I’d love to see something more open and approachable.

The slow rate at which JIRA issues are addressed remains a frustration, and provides a disincentive for contributing. Features that Cognitect cares about get rushed into the language half-baked, while well-thought out patches from years ago languish.

A little concerned over how ‘arbitrary’ some design decisions seem to be and how inflexible the core team is. Running instrumented post-condition specs is such an obvious idea for example but it has been deemed not necessary “from on high”.

The issue tracker is well tended during the earlier workflow stages. There seems to be a bottleneck later on. I hope 2017 will bring the project’s founders to modes of community contribution that are more efficient of the art and tradecraft of the many.


I would say that Clojure’s community is one of it’s greatest assets. There were mostly positive comments for the community, though still some concerns. The Clojurians Slack has been a great resource for a lot of newcomers, and spawned many channels for libraries and topics. IRC is still around, but seems to be less popular, and doesn’t have the breadth of topics that Clojurians does.

Alex Miller is doing a great job addressing the community.

CLJS has come a long way!! to the point we can use it for production development! this community is great! Justin_Smith stands out as ridiculously helpful on IRC … if the world (this community) had more folks like him, it’ll elevate all of our games!

The thing that makes me wary of continuing to invest in Clojure professionally is how few paid opportunities there are for women and people of color. I don’t know what the exact problem is - they are left of networks, don’t have an opportunity to build their skills, or just straight-up sexism and racism - but it is definitely a problem. The current state of things means I will likely not be able to be on teams with women or people of color, and that is a big turn-off for me.

Clojure has the best community after PostgreSQL, in my opinion. I came for the language but I stayed for the community.

Be more inviting to new-comers.. so they stop learning Ruby.


A “Rails for Clojure” was a common request so people can start delivering value quickly. Arachne was commonly raised as one possibility to provide this.

Clojure/ClojureScript it’s very cool, but not very practical nor efficient in many typical business case scenarios. I’m missing a full stack framework like Grails or Ruby on Rails or Django: there’s nothing like that for the Clojure world: it’s not about a project template but about the quick prototyping (with the customer by your side) these frameworks allow.

… There is also no good Clojure Web Development story: Pedestal looks interesting, but not actively developed and unsupported, Arachne is years away from being complete and useful, Luminus/Duct are initial scaffold project generators. It’s hard to delivering some value quickly - user have to dig through all underlying libs and how they work together.

… Clojure web development needs a “Rails” to overcome the chicken-and-egg problem of getting enough developers to be able to hire for it. …

I hope to write a lot more Clojure. No, I hope to do a lot more with less Clojure. And looking forward to using Arachne.

Other targets

Many people are looking to run Clojure on alternative platforms or reduce host dependence. LLVM was a common request. Some are looking to move away from the JVM, while others are looking to move into environments that Java and JavaScript aren’t suited for. This is an interesting request, though one of Clojure’s original goals (and still on the Clojure homepage) is to be a hosted language. I’m not sure whether it’s possible for these two desires to ever meet? Graal and Truffle are also interesting possibilities.

The biggest thing I’ve noticed for beginners on forums / blog comments is they are afraid of the JVM. …

I’ll never rewrite all my Scala into Clojure unless some sort of Cognitect Clojure OFFICIAL LLVM effort is made. Scala Native is [beating] Clojure.

Clojure’s hosted nature is its biggest downfall, in my opinion. As a systems programmer looking to lisp + immutability for saner concurrency, the cost of Clojure’s startup time and memory usage is very high. …

The one thing that I think would drive Clojure to a new level of adoption across the industry would be for someone to do an actual LLVM implementation of Clojure. Not a “close variant” of Clojure, but real Clojure. This would probably yield some performance boost beyond Java, but more importantly it would open up Clojure to environments that are simply not amenable to Java (or Javascript) for whatever reason. Some people have moved in this direction, but either have not completed the work, or have implemented their own “variants” of Clojure. What I wish someone would do is implement something with LLVM that is at least as close to Clojure as Clojurescript is.

I really think an opportunity is being missed by dismissing the c++ ecosystem, and I think that something that should be given somewhat serious consideration to by somebody would be to leverage LLVM with JIT and get a clojurescript running in that setting. There are significant legacy environments to be liberated there.

I would love for there to be some sort of compile-to-bundle with Clojure such that you have a single artifact that doesn’t require an external JVM installation. Like Go programs. An embedded JVM (perhaps).


As we’ve all learned this year, people are worried about types. Spec is the biggest movement in this direction, and the number of type related comments has dropped a lot since last year.

I know that Spec should help a lot with the error messages once we move to 1.9, although people coming from a non-Java background still have a lot of learning to do.

It is just sad that people who love Clojure (Colin Fleming, Steve Yegge, Adam Bard), have to use Kotlin sometimes instead (better startup times, static typing and Java interop like fast multidimensional arrays)

I hope Spec will find its way into tooling, especially Cursive.

Looking forward to learn and use spec

I’d most like to see improvements to the Clojure compiler. Error messages, performance, better Java interop and simple static type checking seem most important.


As I mentioned at the start, the overwhelming majority of comments had positive things to say about Clojure. Alex Miller also deserves a special mention for his work with the community, and maintaining the Clojure infrastructure.

I sincerely thank Clojure(Script) community to make LISP revolution back to live stage and making us realize the importance of focusing on core things which matter

I have been programming since 1979. Clojure is a work of art.

The community has been unbelievably great and I hope it stays true to its roots! Keep up the good work and I can’t wait to see where Clojure/Script goes next!

The community is amazing, with a special shoutout to Alex Miller for being such a great part of it.

Happy Clojure user for over 4 years. Still loving every minute :-).

Finally, I found a comment that I think sums up the general feeling of the community (and my own):

No one and nothing is perfect, but I (for one) am very appreciative of the work that has been done and is on-going around Clojure/ClojureScript and the community in general. People tend to ‘harp’ on the things that aren’t just right (in their opinion) and forget about all the things that are amazing. I just want to say thanks, and keep up the superb work! :-)

I think the future of Clojure is bright.