Back in April, all was well with our community of busy adults learning to code. We were communicating using, a GitHub based chatroom system. And yet every day, someone would ask me “Why aren’t your campers using Slack?”

I’d considered Slack back in October before even starting Free Code Camp, so I was well aware of its limitations. But gradually, my friends persuaded me.

First we messed around with Slack’s API and found an undocumented workaround for their cumbersome email invite system, so we’d be able to automatically add campers to our Slack. Then Harvard’s CS50 class, one of the most popular online courses, started using it. I thought, “OK — if it’s good enough for Harvard, it’s probably safe for us to switch.”

Though their free tier warns that you only get 10,000 messages of searchable archive, and 5 integrations, they clearly state that “there is no limit on how many people you can add to your team on Slack.” So we assumed we wouldn’t need to worry about outgrowing their service.

Our campers were happy and lauded Slack’s hotkeys and mobile experience. They were delighted by Slack’s plaid patterns and warm visual design.

Unfortunately, we hit an undocumented limit – after we hit a certain number of users, Slack stopped allowing us to add new users. We had no choice but to move back to Gitter.

Even though it was 1 a.m. London time, someone from Gitter’s team quickly responded to my desperate tweet, reassuring me that Gitter had no hidden maximum room size. They assured me that things “should be fine”.

It’s worth pointing out that Gitter is a small team. Crunchbase doesn’t show them as having any funding at all. And yet they are slowly winning a battle with competitors like Atlassian’s Hipchat, Basecamp, and Slack, at least for housing large open source communities.

I tried Gitter’s iOS app. It was much faster than before, and included new features like tab completion on @mentions.

Another thing I noticed is that Gitter now allows you the option of hiding your email address, something Slack has yet to implement despite popular demand and the relative ease with which this could be implemented. This was a privacy issue that we’d had to explicitly warn our campers of, but will no longer have to worry about.

A moment ago, I even received this email from one of Gitter’s founders:

Shout out to the Gitter team for welcoming us back, and accomodating the large size of our community.