Mattermost

Details

The server project is provided under under various license terms. Source code is provided under an AGPLv3, with some copyleft exceptions, or under a commercial license which is presumably under non-FOSS terms but this is not made publicly visible. They also state that compiled versions “of the Mattermost platform produced by Mattermost, Inc” are under an MIT license. Some parts of the source are also provided under an Apache license.

Within the project is a “server/enterprise” directory which states that it’s under a Mattermost Source Available License. This is a non-FOSS license which limits use & distribution. This license and folder is not mentioned in the “License” section of the top-level project readme, nor in the top-level “LICENSE.txt” file of the project which is linked from the readme.

From a basic search there appeared to be three cases of the FOSS code depending on non-FOSS code in the “server/enterprise” directory, with three being tests and one being for a command line utility.

The mobile and desktop applications appear to be under an Apache license.

Following the primary path to download the main server component from their project readme guidance, in this case leading to the Linux tar.gz download, the licensing was unclear based on the guidance & when viewing the extracted files. There’s a “ENTERPRISE-EDITION-LICENSE.txt” in the root of the extract with non-FOSS “Mattermost Enterprise Edition (EE) license” terms. There is also a “NOTICE.txt” which does mention the other license terms referenced above, but it’s unclear how they apply to the download, as this is a license detail listing for many dependencies used. Based on the inclusion of the “ENTERPRISE-EDITION-LICENSE.txt”, it’s assumed that the complete distribution of the project provided here is not entirely FOSS, and that this is the “Mattermost Enterprise Edition” despite no obvious mention of that following this download path.

There are various editions of the software provided, which they provide an overview of. There are two self-hosted offerings under the labels of “Mattermost Enterprise Edition” and “Mattermost Team Edition”, the latter of which they state is the open source version. It appears they do provide download for the “Mattermost Team Edition” in their archive, which was only found during review after going through their FAQ.

It appears difficult to find a comparison of the “Mattermost Enterprise Edition” and “Mattermost Team Edition” (FOSS) editions to understand what features are or are not part of the FOSS offering. Several parts of their documentation reference their pricing page, but this does not appear to mention the open source or “Team” versions at all. They do however label the applicable plans on features within their documentation, but you’d need to read through many many pages to gain a full understanding of all differences.

The project advertises itself as “open core” in many areas but then as “open source” in others such as in the GitHub project description.

The project appears to have raised at least $70m in funding from investors which include YC, Battery Ventures, Redpoint and S28 Capital. The project also appears to gain revenue from providing its software as a service, and by selling enterprise variations of the project.