<s>
Mattermost	B-Protocol
is	O
an	O
open-source	B-Application
,	O
self-hostable	O
online	B-Protocol
chat	I-Protocol
service	I-Protocol
with	O
file	O
sharing	O
,	O
search	O
,	O
and	O
integrations	O
.	O
</s>
<s>
It	O
is	O
designed	O
as	O
an	O
internal	O
chat	B-Protocol
for	O
organisations	O
and	O
companies	O
,	O
and	O
mostly	O
markets	O
itself	O
as	O
an	O
open-source	B-Application
alternative	O
to	O
Slack	B-Protocol
and	O
Microsoft	B-Application
Teams	I-Application
.	O
</s>
<s>
The	O
code	O
was	O
originally	O
proprietary	O
,	O
as	O
Mattermost	B-Protocol
was	O
used	O
as	O
an	O
internal	O
chat	B-Protocol
tool	O
inside	O
SpinPunch	O
,	O
a	O
game	O
developer	O
studio	O
,	O
but	O
was	O
later	O
open-sourced	O
.	O
</s>
<s>
The	O
project	O
is	O
maintained	O
and	O
developed	O
by	O
Mattermost	B-Protocol
Inc	O
.	O
</s>
<s>
The	O
company	O
generates	O
funds	O
by	O
selling	O
support	O
services	O
and	O
additional	O
features	O
that	O
are	O
n't	O
in	O
the	O
open-source	B-Application
edition	O
.	O
</s>
<s>
It	O
was	O
also	O
integrated	O
into	O
GitLab	B-Application
as	O
"	O
GitLab	B-Application
Mattermost	B-Protocol
"	O
,	O
although	O
in	O
2017	O
GitLab	B-Application
acquired	O
Gitter	B-Protocol
,	O
another	O
popular	O
chat	B-Protocol
tool	O
,	O
but	O
in	O
2021	O
GitLab	B-Application
sold	O
Gitter	B-Protocol
to	O
Element	O
,	O
the	O
parent	O
company	O
of	O
Matrix	O
.	O
</s>
<s>
In	O
the	O
media	O
,	O
Mattermost	B-Protocol
is	O
mostly	O
regarded	O
as	O
an	O
alternative	O
to	O
the	O
more	O
popular	O
Slack	B-Protocol
.	O
</s>
<s>
Aside	O
from	O
the	O
in-browser	O
version	O
,	O
there	O
are	O
desktop	O
clients	O
for	O
Windows	B-Application
,	O
MacOS	B-Application
and	O
Linux	B-Application
and	O
mobile	O
apps	O
for	O
iOS	B-Application
and	O
Android	B-Application
.	O
</s>
<s>
As	O
of	O
version	O
6.0	O
Mattermost	B-Protocol
includes	O
kanban	O
board	O
and	O
playbook	B-Operating_System
features	O
integrated	O
in	O
main	O
interface	O
.	O
</s>
<s>
Mattermost	B-Protocol
has	O
been	O
tested	O
for	O
community	O
use	O
by	O
Wikimedia	O
as	O
Wikimedia	O
Chat	B-Protocol
on	O
Wikimedia	O
Cloud	O
Services	O
as	O
of	O
late	O
summer	O
2020	O
.	O
</s>
<s>
Among	O
other	O
adopters	O
,	O
companies	O
having	O
adopted	O
Mattermost	B-Protocol
include	O
CERN	O
with	O
a	O
reported	O
"	O
10,000	O
monthly	O
active	O
users	O
"	O
having	O
chosen	O
Mattermost	B-Protocol
under	O
the	O
reasoning	O
“	O
did	O
n’t	O
want	O
to	O
use	O
another	O
service	O
that	O
locked	O
in	O
our	O
data	O
”	O
,	O
and	O
the	O
U.S.	O
Department	O
of	O
Defense	O
.	O
</s>
