Mattermost

I use Slack because it offers the best experience, even on the free tier (which we're still using). As a comparison, I have had in depth experience with HipChat, Stride, Skype, Google Chat (the new service), Google Hangouts (the old service). For self hosted, Mattermost is open source and claims to support most Slack integrations, but I have not extensively investigated this claim.

I use Zulip instead of Slack, Mattermost, or RocketChat because of its first class threading. One week after switching to Gmail (in 2004) I realized I was never (willingly) going to use an unthreaded email product again. I had that same experience the first time I saw Zulip.

Zulip is also fully open-source, with a well-maintained (e.g. 90+% test coverage, fully static python), easily extensible code-base. In many companies, your communication platform (chat or email) is the center of the workplace -- no one asks for a chat integration into their calendar, they ask for a calendar integration into their chat. A fully open-source codebase means you can customize Zulip to your needs, and are never at the whim of a corporate maintainer who can't or won't fix simple bugs, or who will charge you tens of thousands of dollars for making minor customizations.

Slack is the industry standard for managed instant messaging (IM). A good alternative would be to self (or cloud) host an open source IM such as Mattermost but as always it would be a good idea to do a cost benefit analysis between the solutions.

Some of the main things to consider:

• Having a good SDK for plugin creation
• Having good integrations with existing tools ( JIRA , GitHub , OpsGenie , etc.)
• Cost
• Maintenance and administration
• Covers all your businesses use cases

Why we piggybacked on the open source Mattermost for Uber's chat needs, which we open sourced as uChat ( GitHub : https://github.com/uber-uchat/ -- contributing some of our changes back to Mattermost as well in the process.)

With operations in over 620 cities, it was paramount for us to identify a chat solution that would enable Uber employees to reliably communicate on desktop and mobile regardless of where they were in the world. To accomplish this, we established a few core requirements. To start, we needed something that could scale to support our growing employee population and, as a byproduct, control costs. We also needed a platform that could easily integrate with a variety of internal engineering, business, and operational tools.

While we evaluated Internet Relay Chat (IRC) and many other popular chat clients, it became clear that there was no turnkey third-party solution able to meet Uber’s core requirements.

So after testing multiple off-the-shelf alternatives, we built uChat, our custom in-house messaging platform, by leveraging open source platform Mattermost and Puppet Labs , the Uber standard for deployment configuration management. In this article, we discuss how in just three months our team transitioned the company to a new solution capable of reliably delivering over one million messages per day to tens of thousands of users, all in one unified chat environment:

https://eng.uber.com/uchat/

We need to develop a social media like chat in which users can message each other or create a channel. We are planning to use RocketChat or Mattermost under the hood to develop a custom UI. How do notifications work in that case? Has anyone done it? Or is there any better way to implement it.

Recently we finished long research on chat tool for our students and mentors. In the end we picked Mattermost Team Edition as the cheapest and most feature complete option. We did consider building everything from scratch and use something like Pusher or Twilio on a backend, but then we would have to implement all the desktop and mobile clients and all the features oursevles. Mattermost gave us flexible API, lots of built in or easy to install integrations and future-proof feature set. We are still integrating it with our main platform but so far the team, existing mentors and students are very happy.