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
4313 mastodon.social
1400 hachyderm.io
821 fosstodon.org
611 mastodon.online
550 mstdn.social
507 infosec.exchange
478 mas.to
472 ruby.social
399 mastodon.gamedev.place
361 techhub.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
805 mastodon.social
329 hachyderm.io
209 fosstodon.org
133 infosec.exchange
129 mstdn.social
112 mastodon.online
107 mas.to
104 techhub.social
57 mastodon.gamedev.place
40 mastodon.world

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
642 mastodon.social
346 hachyderm.io
118 fosstodon.org
118 techhub.social
99 mas.to
90 mastodon.online
87 mstdn.social
83 phpc.social
62 ruby.social
55 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
500 hachyderm.io
365 mastodon.social
72 fosstodon.org
70 mastodon.gamedev.place
61 infosec.exchange
58 mastodon.online
49 mas.to
43 mstdn.social
37 techhub.social
24 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
489 ruby.social
178 mastodon.social
126 hachyderm.io
28 mas.to
23 infosec.exchange
20 fosstodon.org
20 mastodon.online
17 techhub.social
15 mstdn.social
13 mastodon.world

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

Mastodon instances with most PHP developers

Count Instance
374 phpc.social
280 mastodon.social
58 fosstodon.org
49 hachyderm.io
43 mas.to
37 mastodon.online
36 mstdn.social
23 infosec.exchange
19 techhub.social
17 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 🙏