Mastodon Instances with Software Developers

Mastodon is a social network similar to Twitter, but with the key difference that there is no single entity running it. Instead, Mastodon is comprised of thousands of instances. According to mastodon.help the total number of instances is currently 12.206.

Since each instance has its own rules and code of conduct it can be a bit intimidating to pick the right one for you.

The general advice is that picking an instance doesn't matter, since the ActivityPub protocol behind Mastodon allows you to follow accounts from any other instance. But Mastodon clients allow you to see posts made by other users on the instance (local timeline) so some users prefer to join instances where users have common interests.

Mastodon instances with most developers

If you are a software engineer or someone learning or interested in software development you might want to create an account on an instance with other software developers so that your local timeline is full of relevant content.

For Fedidevs I have indexed some of the most popular Mastodon instances and used regexes to try and find accounts that belong to software developers.

I indexed only a small percentage (0.225%) of all Mastodon instances, but this set of instances includes the majority of English-speaking users on Mastodon (see the full list of instances in the FAQ page).

The results

Count Instance
3858 mastodon.social
1065 hachyderm.io
856 fosstodon.org
439 mastodon.online
403 infosec.exchange
398 mstdn.social
376 ruby.social
347 mas.to
300 mastodon.gamedev.place
253 phpc.social

No surprise that mastodon.social is on top here. It's one of the largest Mastodon instances with more than 1 million users. That's 1/6 of Mastodon's total users according to mastodon.help. Even though mastodon.social has the most developers of any instance, it also has the most users so the percentage of developers is not that high and your local timeline will most likely not have content relevant to you.

hachyderm.io is an LGBTQIA+ and BLM safe space focused on tech industry professionals worldwide.

mastodon.online is another very popular general purpose instance.

phpc.social and ruby.social are instances for people interested in Ruby and PHP programming languages.

fosstodon.org a community for anyone interested in technology; particularly free and open source software. The custom emojis on this instance are amazing 👌

infosec.exchange focuses on info/cyber security. If that's what you are interested in this is probably the best instance for you!

techhub.social is primarily for passionate technologists, but according to the instance description everyone is welcome.

Mastodon instances with most Python developers

Count Instance
624 mastodon.social
219 hachyderm.io
197 fosstodon.org
75 infosec.exchange
71 mstdn.social
69 mastodon.online
57 techhub.social
53 mas.to
35 chaos.social
28 mastodon.gamedev.place

The Python community has recently started to migrate away from Twitter and a lot of prominent Python community members no longer post on Twitter.

Besides the two largest instances most Python developers seem to hang out on fosstodon.org. This is where some of the largest Python-related accounts live, including the official account for the Python Software Foundation, Michael Kennedy, Brett Cannon, and others.

Mastodon instances with most JavaScript developers

Count Instance
380 mastodon.social
143 hachyderm.io
75 fosstodon.org
53 phpc.social
47 ruby.social
44 techhub.social
43 mas.to
38 mstdn.social
38 mastodon.online
29 infosec.exchange

The top two largest instances for JavaScript developers are the same as the Python ones, but fosstodon.org isn't as popular with JavaScript developers as it is with Python developers.

Mastodon instances with most Rust developers

Count Instance
334 hachyderm.io
292 mastodon.social
60 fosstodon.org
47 mastodon.gamedev.place
36 infosec.exchange
36 mastodon.online
25 mas.to
20 mstdn.social
18 tech.lgbt
18 chaos.social

Rust developers seem to prefer hachyderm.io over mastodon.social and it seems to be the only programming language with these instances switched.

Mastodon instances with most Ruby developers

Count Instance
354 ruby.social
133 mastodon.social
83 hachyderm.io
16 fosstodon.org
13 mastodon.online
11 infosec.exchange
8 mastodon.gamedev.place
8 mas.to
7 mstdn.social
6 techhub.social

No surprise that Ruby developers prefer the ruby Mastodon instance - ruby.social.

Mastodon instances with most PHP developers

Count Instance
265 phpc.social
212 mastodon.social
39 fosstodon.org
21 mstdn.social
20 mastodon.online
17 hachyderm.io
16 mas.to
13 infosec.exchange
12 mastodonapp.uk
10 mastodon.gamedev.place

Similar to Ruby developers PHP developers also have their instance phpc.social. Unlike the Ruby community, it seems like the PHP community is more spread out and the official PHP instance takes up a smaller percentage of users than the ruby.social instance in the Ruby community.

Other popular languages

Fedidevs also allows filtering by Java, C#, Golang, and others. But the amount of accounts isn't as high as the ones listed in this article so I've omitted it for brevity. Let me know if you would still want to see the statistics for these.

If you have any other suggestions on how to improve this blog post or fedidevs.com don't be shy to reach out 🙏