Mattermost

Avantages

You can host it for free.
Markdown support.
Gitlab Integration and updates.
Easy to administrate.

Inconvénients

There are many mature alternatives.
Lacks some features or has them but you need to do way to much setup.
Doesn't feel as polished as others.
Mobile app is getting better, but still not up to the competition.

Avantages

Interactive media that allows instant communication with teammates and leadership, whether it was a question or just sharing of daily life.

The ability to host channels that was based on teams, programs, and specified topics. All individuals were able to have private groups to chat with friends, co workers, or teams.

Inconvénients

The scroll in chats often moved so very quickly that questions and responses were missed.

Inability to customize responses such as color, fonts, etc.

Avantages

Very supportive and open-minded team which helps where they can. Also open for new feature ideas. Almost en par with Slack but self-hosted which is a big bonus for companies in privacy concerned organizations.

Inconvénients

The iOS app could be better. Complicated installation/update if you don't do it via gitlab-omnibus package.

Avantages

The use of web sockets and consistency between platforms and ability to self host the software. Open source is also a high point.

Inconvénients

Lack of asymmetric end-to-end encryption. Would like to see server side ability to enable/disable this feature, as well as seeing it as either mandatory or opt-in for each chat session. Would be best if each client would generate a key-pair and give public cert to the server and each other client signed/encrypted it with the public key.

Avantages

It is free and opensource, so you know what you are running and you can contribute to it whenever you think there's something that can be improved. It has all the necessary tools to be the organization's chat platform and whenever you find and odd problem, the support is there to help you.

Inconvénients

It is not yet as intuitive to use integrations as it is with slack. The UI although has improved greatly over time, it still has room to improve.

Avantages

It's very simple to use and much much cheaper than its competition. Persistent chat is beneficial when working with teams across multiple time zones -- email notifications when I'm not signed in is great.

Inconvénients

There is something that's somewhat intangible but for some reason Slack feels better. Slack seems more elegant, but overall, this is the only negative thing I could find about the software. Overall it meets and exceeds my team's needs for a fraction of the price.

Avantages

The cost. The fact it is free is what got my attention.

After that I found out I could self-host it, which made it even more useful. I can use Mattermost for my team(s) and still control my data. The interface is attractive. You can use a Mattermost app or you can use the web interface.

Inconvénients

The install and maintenance is on me. You need to have enough time for the install and maintaining the server for the system. If you don't have the time, this is probably not the best option for you.

Avantages

One of the most critical aspects of Mattermost: it's self-hosted. Yes, that means additional work for hosting, but it also ensures our internal communication stays internal. We use Mattermost for almost all of our discussion​, and it has dramatically improved our workday.

Inconvénients

Mobile clients exist, but there are not necessarily​ great. I often use the website instead of the mobile client, because it is quicker and the status of my colleagues is actually shown correctly.

Avantages

It's very easy to use, and as far as I can tell works alot like slack. I'm not sure if it has as many plug-in options but that's not something I'd use anyway. Great for team collaboration and general communication.

Inconvénients

I get LONG LISTS of rooms and chats and there is no easy way to search for people aside fom doing a control-f. I can search within chats, but I think it needs to be easier to search FOR chats

Avantages

The software is easy to use, similar to the commercial app Slack. It provides good thread tracking and the interface is clean and easy to understand.

Inconvénients

For its purpose, I have found nothing about the software that I can find to complain about. It does exactly what I expected. I suppose there have been times when searching for older posts has been difficult due to the search returning a lot of matches and having to scroll through the matches.

Avantages

it is very well designed, it allows usage of emojis and gifs, so communication within platform is fun after hard working day

Inconvénients

i cant find contacts easily, it's a little bit hard to join server if 8t is not allready joined.

Avantages

Mattermost makes it convenient to communicate with different teams around the world. We can get snap updates when needed, create new channels to focus our communications, and it has a dark mode.

Inconvénients

Sometimes I get connections difficulties.

Avantages

I did an evaluation for a replacement for our Hipchat server as Atlassian is phasing out Hipchat for on-site chat. In doing a direct shootout between Mattermost and a competitor, I found Mattermost much easier to install and administer. Mattermost's team has been very responsive in the evaluation process. There are a large number of plugins available to connect other development tools to Mattermost. It's clear it's a product that is getting actively maintained, with new features and functionality coming nicely down the pipeline to the end users.

Inconvénients

The Jira integration is currently not as fully-featured as Hipchat's was. That said, I believe that a better integration is coming down the pipeline. The default video chat/screen share plugin is Zoom. I would prefer having other options.

Avantages

it is one of the easiest and common communication tool whithin the company, it has customatizable ui and integrated emojis. so it very fun way to communicate.

Inconvénients

there are some minor glitches but it doesn't affect overall experience.

Avantages

i like that i can reach easily all employees and communicate with them. i like numerous of stickers and smiles and ability to make group chats.

Inconvénients

it isn't easy to use. when i receive message sometimes i miss notifications. when i click pop up window it doesn't begin conversation, i have to find message in contact list. this is inconvenience.

Avantages

What I like the most about this collaboration software is the simple and logical UI, which is not overloaded with lots of unnecessary features. It has all we need for successful communication. Also, it's very easy to deploy and integrate. Ensures really secure collaboration.

Inconvénients

Great tool overall, perfectly performs its functions, didn't face any issues or drawbacks. Highly recommend.

Alternatives envisagées 

Avantages

When it's too much to send an email or you can't be bothered to get out of your chair, Mattermost is perfect. It allows all our staff to quickly chat about things without clogging up inboxes or having them on their phones. Groups and channels are great, especially for management needs.

Inconvénients

The ability to preview non-image files would be nice, some files,​ have to be downloaded to be previewed.

Avantages

Great Slack alternative
Works good
Great app
We have been using Mattermost for quite a while now and are really happy with it

Avantages

It is an easy to use, open-source and free messenger, which can be setup either on-premises or hosted on a cloud platform, while also being docker friendly. Community extensions and plugins, as well as optional commercial enterprise-level support, provide infinite extensibility and flexibility options.

Inconvénients

A few more service integrations, like audio/video conferencing, contacts/calendar sharing, attachments managing, better in-chat previews would be positive moves, although these features are getting improved version by version.

Avantages

we had to change from past solution to mattermost, it was huge jump. mainly it's chatting way between company so its mainly informal and matter mostly offers modern chat features, custom emoji emoji etc.

Inconvénients

getting mobile app and making it running is little bit hard because you need to know your chat server and its little bit hard for most people.

Avantages

The interface is self explainable. Easy to use and operate. Highly reliable

Inconvénients

Integration is the difficult part. Once it's setup then it's easy to work. Mobile app is working fine. Window app is not up to mark

Avantages

Easy to use, Open source, ability to tag people in comments and respond with emojis (this makes it fun to work with colleagues). And being a open source we can easily customize to the needs of our organization.

Inconvénients

The pricing of it seems to be a bit on high size. I'm able to keep more than 3 chats on the left panel, so have to search for people almost all the time to initiate a chat. Since there names offen disappears from the quick access panel.

Avantages

It is free, open-source, it got a lot of features like slack and it is light

Inconvénients

A bad user interface, a lot of bugs, sometime you need to restart it in order to make sure that everything works as expected

Avantages

I like the interface and how you are able to customize it

Inconvénients

I think the search bar sometimes is not efficient

Avantages

It's open source, free, actively maintained, ability to self host it and tailor to our needs, extensible through various integrations.

Avantages

Incredibly easy to use software and ties into all my workflows. Hundreds of integrations, great UI, rich text formatting and Open Source. Love Mattermost!!

Inconvénients

Nothing. Could not be happier with Mattermost and have been using it for over 2 years.

Avantages

It is opensource, it has no limits like Slack and it allows similar experience/functions. It is not easy to set-up but once started it works with no issues on desktops/laptops.

Inconvénients

Android app is not connecting to some servers (all I built). SSL certificate handling is a bit tricky.
Default way of creating users is sending them link (creating user/pass would be a good option).

Avantages

We can easily integrate its available APIs to be used within custom applications. It provides many chat features like one-on-one chat as well as Group chat features including file sharing features. The billing is as per the user count.

Inconvénients

Requires more additional features like last seen, last read, etc that are available within the latest chat applications.

Avantages

+ Open Source
+ Can be set up for free even for Commercial use
+ Can be hosted on-premise
+ Good community support - Apps and Integrations brings great support to exchange data with external systems for software development teams

Inconvénients

- The interface is not as refined as Slacks's
- Video and audio conferencing is not integral part of the software and requires external integrations

Avantages

I can spin up a new chat room easily for developers to collaborate on a new project or discuss a certain topic without a bunch of hassle. We can share formatted code snippets, paste files and images into our chats, search our history, and do all kinds of useful things.

Inconvénients

I do not really have a con. I'm even using the free, built-in version that comes with the free version of GitLab and have no complaints.

Avantages

It does everything that you need a chat software to do. You can set up general rooms as well as direct message. Sending text as well as images and files is also possible. The selling point for us was that we can host it on our servers, which was a big plus.

Inconvénients

There were some minor configuration problems that, while we did get it up and running, left things like a banner across the top of a user's screen indicating he didn't have connect, even when he did. A minor frustration.

Avantages

a. Simple workspace platform, especially for remote workers
b. Many integrations can be made and compatible with Mattermost
c. Highly customizable due to its open-source based.

Inconvénients

d. UI is not really appealing. The UI theme kind of always remembers me that I'm working. It's not necessarily a bad thing but it could be less "work-theme", so we could feel a little bit relax.
e. Cannot make a thread out of a message.

Avantages

I always prefer to use open source software where possible. Mattermost was a great option to have in the running with the likes of HipChat and Slack. The community was great and it was easy to contribute.

Inconvénients

The mobile experience didn't seem quite as polished as other collaboration software at the time, it's possible that this aspect has improved recently.

Avantages

A great messaging tool for internal chatting with the co-workers. It has a great user interface and I like the fact that you can find a lot of gifs and create your own sticker. Very convenient and fun

Inconvénients

Sometimes it's difficult to keep track of thread messages. It would be better if threads can be more visible

Avantages

Matter most lets you own your own data. Self-host Mattermost means not letting a third-party control what actually matters in a chat open. The open dvevelopment model gives insight into the upcoming relase cycle, see if others have solved integration issues that you may be attempting, file bug reports and follow the progress in fixing or even contributing a fix back yourself.

Inconvénients

Mattermost still has some rough edges regarding their mobile clients. The new native app is definitely better than the previous web-view one though.

Avantages

Mattermost is like a chatroom with different channels which you can join, in which channels are defined by relative subject at work. It was a quick way for us to get in touch via live chat with a person or group. Did I mention that it's open-source and works well on almost all platforms?

Inconvénients

I have not experienced any issues at the moment.

Avantages

Nice options and functionality useful for everyday use

Inconvénients

Inability to turn off popup notifications

Avantages

Open Source community driven.
Very easy to install and maintain.
Very stable.
Easy to integrate.

Inconvénients

Some fancy features might take forever to be implemented.
Lacks some nice to have admin features for large user groups.

Avantages

Mattermost was really easy to setup, the additonal https configurations are also well documented. As for the user side,it is similar to slack

Inconvénients

Single Sign On functionality is based on plugin, which sometimes doesn't work that well. Other than that,no problems performance or functionality-wise.

Avantages

El chat, es muy fácil la comunicación interna entre departamentos lo que me facilita presupuestar diferentes partidas antes de dar precio al cliente

Inconvénients

De momento nada, estamos valorando las opciones

Avantages

I like it keeps all the history of the channels so when new people join they can access the previous messages.
The possibility of creating personalised emojis.
The fact you can flag some posts, making them easier to find whenever you need.

Inconvénients

I think the mobile platform is a bit slow to use, it could be a bit faster.

Avantages

New features coming without increasing complexity for the user, the open source DNA, it's capacity to integrate anywhere.

Inconvénients

The mobile app could be faster, and I miss the capacity to paste easily something with more than 4000 characters.

Avantages

Mattermost is my main software for communication within our company. The software works perfectly and allows groups and private messaging between individuals. Most importantly Mattermost is HIPAA complaint.

Inconvénients

The only downfall of the Mattermost software is that it is not always obvious when there is a message waiting. They could improve their notification system.

Avantages

This piece of software is very easy to use. There is virtually no learning curve to begin using this software.

Inconvénients

There is nothing that I dislike about this software. It is easy to use which is what everyone looks for in software.

Avantages

The ability of Mattermost to detect that you paste an image URL and display the image without getting out of Mattermost, and the fetching of Oembed/Opengraph/whatever data of URLs, providing summary of pages.
And the extendability with hooks.

Inconvénients

Well, sometimes, I can't find the message I'm looking for with the research feature, but it surely is caused by bad search terms. Putting flags on important messages helps not loosing them.

Avantages

What we loved with Mattermost is the easiness of deployment. In a couple of minutes you are up and running

Inconvénients

Tons of integration you really don't know where to start.

Avantages

the main think i like in Mattermost is design it feels lighter, it makes me feel happy, emojis are great way to impress and make communication more informal, also ability to use gifs is one of most useful features

Inconvénients

compared to other communicators i used it feels little bit harder to use, its easy nothing very difficult but it feels like i need some extra effort to find person and use direct messaging.

Avantages

So intuitive interface and so less clutter. The teams love mattermost for many things, integrations, easy to use interface, stability of the software.

Inconvénients

1. The ability for anyone to delete a channel.
2. Lack of SAML support for team edition

Avantages

It is simple to use.
It is compatible with linux.

Inconvénients

Hard to see the history of the chats.
You can not search in a concrete chat.
Slow performance.
Only chat available you will need another tools for meetings.
Bad integration with gnome desktop.

Avantages

It's open source, so you can tweak, audit, and customize to your heart's content. It can be deployed on-prem so you can meet whatever security requirements you have.

Inconvénients

Doesn't feel as polished as Slack. There are a lot of little UI quirks that bother me. Aside from that, there's not much not to like.