Mattermost vs. Rocket Chat: Which Is the Best Self-Hosted Slack Alternative?

Ever since Slack hit the market, it has been the first choice of many businesses who need an efficient way to communicate within their organization. Not everyone loves Slack, though. Many people say it is too pricey. Maybe it’s missing the functionality you need for your business.

One of the most popular complaints is the limitation set on the number of messages you can search. The free version sets this number at 10,000. If you need to be able to search more than that, you have to upgrade, and the cost can be prohibitive. Others want to self-host their chat platform to gain more control over the environment, and Slack won’t let you do that.


Whatever your reason, there are many alternatives out there that are self-hosted, are less expensive, and have features that Slack does not have. We have previously covered RocketChat and Mattermost. Let’s see how they perform against each other and which one is the better Slack alternative.

What Both Programs Have

First, let’s look at features that both RocketChat and Mattermost have in common.

They are both open-source team chat apps that are deployable in your own private cloud environment. There are mobile apps available for both iOS and Android. They both offer document sharing among team members. They have a fully customizable web-based architecture that uses LDAP (Lightweight Directory Access Protocol) and SAML (Security Assertion Markup Language) for password authentication. Both apps offer notifications through desktop push, mobile push, and email.

Here’s where the differences come in.


The RocketChat app is written in Meteor app, a Javascript framework, and uses a MongoDB backend. The program operates across multiple platforms including Linux, FreeBSD, macOS, and Windows, which is more than Mattermost does.


RocketChat also allows you to sign in from third-party apps such as Facebook, GitHub or Google.

This Slack alternative can be a bit difficult to set up on your own but not impossible with some technical skills.

If you have a lot of users and want to self-host your chat for privacy and security reasons, RocketChat is better. Especially if, like many businesses, you are using community chat rooms to engage with customers. Those rooms could have tens of thousands of users, making Rocketchat more financially practical because you do not have to pay a per user fee.

An impressive feature of this app is that if you have large chat rooms, RocketChat can search all the messages to get the information you need.

The biggest problem with RocketChat is that it does not have any official customer service and limited documentation. You can usually find your answers on sites such as GitHub, though.

Some of the useful features included in RocketChat include:

  • Audio conferencing, video conferencing, and screen sharing
  • Real-time translation in 35 languages
  • Live chat widgets for websites
  • Integration with apps such as GitHub and Zapier

RocketChat is a completely free software. There is no separate free and paid versions.


One way that Mattermost differs from RocketChat is that it uses MySQL or PostgreSQL for its backend and an ACID database. Also, it is written in Go and React, which is a level lower than Meteor.


Mattermost is a better choice for enterprises who want a robust solution with no per-user fees like Slack. Another reason you may want to use Mattermost is lower CPU usage because they use Go and React instead of Meteor.

You can run Mattermost on Linux, Windows, and other platforms, as well as on private cloud deployments such as AWS, Azure and others such as CloudFoundry or Kubernetes. It supports sign in from third-party apps including Google, Office365, GitLab.

Maybe most importantly, depending on your situation, is that Mattermost has more documentation available for setup, maintenance, and administrative tasks. You don’t need to go on a hunt for the information you need when you have an issue.

This app can be expensive to use, especially if you have a lot of users.

Some of Mattermost’s useful features:

  • You own all your data even after you cancel the subscription
  • Can import data from Slack
  • It has custom emojis

Mattermost is not entirely free like RocketChat. They have a team edition that is free and an enterprise edition which costs between $20-$80 per month. The free solution doesn’t have useful features like the ability to set permissions or preventing users without admin privileges to change settings in chat rooms or deleting them altogether.

As with most apps of this type, what is best for you depends on what you need. You need to take into consideration your budget, the number of users you need to accommodate and the amount of tech support you have to set it up and troubleshoot problems. RocketChat would be a great choice for almost every company with its many features and totally free cost. However, if you have limited tech support, you may find that the price for Mattermost is worth it to keep your company chats up and running.

Tracey Rosenberger
Tracey Rosenberger

Tracey Rosenberger spent 26 years teaching elementary students, using technology to enhance learning. Now she's excited to share helpful technology with teachers and everyone else who sees tech as intimidating.

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