matrix-org/synapseSynapse: Matrix homeserver written in Python/Twisted.
element-hq/synapse <https://github.com/element-hq/synapse>_Synapse is an open-source Matrix <https://matrix.org/>_ homeserver developed
from 2019 through 2023 as part of the Matrix.org Foundation. The Matrix.org
Foundation is not able to resource maintenance of Synapse and it
continues to be developed by Element <https://github.com/element-hq/synapse>;
additionally you have the choice of other Matrix homeservers <https://matrix.org/ecosystem/servers/>.
See The future of Synapse and Dendrite <https://matrix.org/blog/2023/11/06/future-of-synapse-dendrite/>_
blog post for more information.
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Briefly, Matrix is an open standard for communications on the internet, supporting
federation, encryption and VoIP. Matrix.org has more to say about the goals of the Matrix project <https://matrix.org/docs/guides/introduction>, and the formal specification <https://spec.matrix.org/> describes the technical details.
.. contents::
The Synapse documentation describes how to install Synapse <https://matrix-org.github.io/synapse/latest/setup/installation.html>. We recommend using
Docker images <https://matrix-org.github.io/synapse/latest/setup/installation.html#docker-images-and-ansible-playbooks> or Debian packages from Matrix.org <https://matrix-org.github.io/synapse/latest/setup/installation.html#matrixorg-packages>_.
.. _federation:
Synapse has a variety of config options <https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html>_
which can be used to customise its behaviour after installation.
There are additional details on how to configure Synapse for federation here <https://matrix-org.github.io/synapse/latest/federate.html>_.
.. _reverse-proxy:
It is recommended to put a reverse proxy such as
nginx <https://nginx.org/en/docs/http/ngx_http_proxy_module.html>,
Apache <https://httpd.apache.org/docs/current/mod/mod_proxy_http.html>,
Caddy <https://caddyserver.com/docs/quick-starts/reverse-proxy>,
HAProxy <https://www.haproxy.org/> or
relayd <https://man.openbsd.org/relayd.8>_ in front of Synapse. One advantage of
doing so is that it means that you can expose the default https port (443) to
Matrix clients without needing to run Synapse with root privileges.
For information on configuring one, see the reverse proxy docs <https://matrix-org.github.io/synapse/latest/reverse_proxy.html>_.
The instructions for upgrading Synapse are in the upgrade notes_.
Please check these instructions as upgrading may require extra steps for some
versions of Synapse.
.. _the upgrade notes: https://matrix-org.github.io/synapse/develop/upgrade.html
Synapse uses a number of platform dependencies such as Python and PostgreSQL,
and aims to follow supported upstream versions. See the
deprecation policy <https://matrix-org.github.io/synapse/latest/deprecation_policy.html>_
for more details.
Matrix serves raw, user-supplied data in some APIs -- specifically the content repository endpoints_.
.. _content repository endpoints: https://matrix.org/docs/spec/client_server/latest.html#get-matrix-media-r0-download-servername-mediaid
Whilst we make a reasonable effort to mitigate against XSS attacks (for
instance, by using CSP_), a Matrix homeserver should not be hosted on a
domain hosting other web applications. This especially applies to sharing
the domain with Matrix web clients and other sensitive applications like
webmail. See
https://developer.github.com/changes/2014-04-25-user-content-security for more
information.
.. _CSP: https://github.com/matrix-org/synapse/pull/1021
Ideally, the homeserver should not simply be on a different subdomain, but on
a completely different registered domain_ (also known as top-level site or
eTLD+1). This is because some attacks_ are still possible as long as the two
applications share the same registered domain.
.. _registered domain: https://tools.ietf.org/html/draft-ietf-httpbis-rfc6265bis-03#section-2.3
.. _some attacks: https://en.wikipedia.org/wiki/Session_fixation#Attacks_using_cross-subdomain_cookie
To illustrate this with an example, if your Element Web or other sensitive web
application is hosted on A.example1.com, you should ideally host Synapse on
example2.com. Some amount of protection is offered by hosting on
B.example1.com instead, so this is also acceptable in some scenarios.
However, you should not host your Synapse on A.example1.com.
Note that all of the above refers exclusively to the domain used in Synapse's
public_baseurl setting. In particular, it has no bearing on the domain
mentioned in MXIDs hosted on that server.
Following this advice ensures that even if an XSS is found in Synapse, the impact to other applications will be minimal.
The easiest way to try out your new Synapse installation is by connecting to it from a web client.
Unless you are running a test instance of Synapse on your local machine, in
general, you will need to enable TLS support before you can successfully
connect from a client: see
TLS certificates <https://matrix-org.github.io/synapse/latest/setup/installation.html#tls-certificates>_.
An easy way to get started is to login or register via Element at
https://app.element.io/#/login or https://app.element.io/#/register respectively.
You will need to change the server you are logging into from matrix.org
and instead specify a Homeserver URL of https://<server_name>:8448
(or just https://<server_name> if you are using a reverse proxy).
If you prefer to use another client, refer to our
client breakdown <https://matrix.org/ecosystem/clients/>_.
If all goes well you should at least be able to log in, create a room, and start sending messages.
.. _client-user-reg:
By default, registration of new users via Matrix clients is disabled. To enable it:
In the
registration config section <https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#registration>_
set enable_registration: true in homeserver.yaml.
Then either:
a. set up a CAPTCHA <https://matrix-org.github.io/synapse/latest/CAPTCHA_SETUP.html>_, or
b. set enable_registration_without_verification: true in homeserver.yaml.
We strongly recommend using a CAPTCHA, particularly if your homeserver is exposed to the public internet. Without it, anyone can freely register accounts on your homeserver. This can be exploited by attackers to create spambots targetting the rest of the Matrix federation.
Your new user name will be formed partly from the server_name, and partly
from a localpart you specify when you create the account. Your name will take
the form of::
@localpart:my.domain.name
(pronounced "at localpart on my dot domain dot name").
As when logging in, you will need to specify a "Custom server". Specify your
desired localpart in the 'User name' box.