ejabberd is an Extensible Messaging and Presence Protocol (XMPP) application server and an MQ Telemetry Transport (MQTT) broker, written mainly in the Erlang programming language. It can run under several Unix-like operating systems such as macOS, Linux, FreeBSD, NetBSD, OpenBSD and OpenSolaris. Additionally, ejabberd can run under Microsoft Windows. The name ejabberd stands for Erlang Jabber Daemon (Jabber being a former name for XMPP) and is written in lowercase only, as is common for daemon software. ejabberd is free software, distributed under the terms of the GNU GPL-2.0-or-later. , it is one of the most popular open source applications written in Erlang. XMPP: The Definitive Guide (O'Reilly Media, 2009) praised ejabberd for its scalability and clustering feature, at the same time pointing out that being written in Erlang is a potential acceptance issue for users and contributors. The software's creator, Alexey Shchepin was awarded the Erlang User of the Year award at the 2006 Erlang user conference. ejabberd has a number of notable deployments, IETF Groupchat Service, BBC Radio LiveText, Nokia's Ovi, KDE Talk and one in development at Facebook. ejabberd is the most popular server among smaller XMPP-powered sites that register on xmpp.org. With the next major release after version 2 (previously called ejabberd 3), the versioning scheme was changed to reflect release dates as "Year.Month-Revision" (starting with 13.04-beta1). It was also announced that further development will be split into an "ejabberd Community Server" and an "ejabberd Commercial Edition [which] targets carriers, websites, service providers, large corporations, universities, game companies, that need high level of commitment from ProcessOne, stability and performance and a unique set of features to run their business successfully." Project history Alexey Shchepin started ejabberd in November 2002 for three main reasons: success with Tkabber (his previous project, an XMPP client), a rather unstable first alpha release of jabberd2, and his wish to play with Erlang features. Shchepin has stated that he would have not started ejabberd without Erlang. Ejabberd hit version 1.0 in December 2005. Features ejabberd has a high level of compliance with XMPP. It provides a web interface which can be translated into other languages. ejabberd supports distributed computing by clustering, supports live upgrades, shared roster groups and provides support for virtual hosts. Database management systems supported include PostgreSQL and MySQL, and ODBC is supported for connectivity to other systems. LDAP authentication is supported, as is login via SSL/TLS, SASL and STARTTLS. ejabberd