Remove documentation for 'feature_state_counters'
Element (formerly known as Vector and Riot) is a Matrix web client built using the Matrix React SDK.
Element has several tiers of support for different environments:
- Definition: Issues actively triaged, regressions block the release
- Last 2 major versions of Chrome, Firefox, and Edge on desktop OSes
- Last 2 versions of Safari
- Latest release of official Element Desktop app on desktop OSes
- Desktop OSes means macOS, Windows, and Linux versions for desktop devices that are actively supported by the OS vendor and receive security updates
- Definition: Issues accepted, regressions do not block the release
- Element as an installed PWA via current stable version of Chrome
- Mobile web for current stable version of Chrome, Firefox, and Safari on Android, iOS, and iPadOS
- Not supported
- Definition: Issues only affecting unsupported environments are closed
- Everything else
The easiest way to test Element is to just use the hosted copy at https://app.element.io.
develop branch is continuously deployed to https://develop.element.io
for those who like living dangerously.
To host your own instance of Element see Installing Element Web.
To install Element as a desktop application, see Running as a desktop app below.
Important Security Notes
We do not recommend running Element from the same domain name as your Matrix homeserver. The reason is the risk of XSS (cross-site-scripting) vulnerabilities that could occur if someone caused Element to load and render malicious user generated content from a Matrix API which then had trusted access to Element (or other apps) due to sharing the same domain.
We have put some coarse mitigations into place to try to protect against this situation, but it's still not good practice to do it in the first place. See https://github.com/vector-im/element-web/issues/1977 for more details.
Configuration best practices
Unless you have special requirements, you will want to add the following to your web server configuration when hosting Element Web:
X-Frame-Options: SAMEORIGINheader, to prevent Element Web from being framed and protect from clickjacking.
frame-ancestors 'self'directive to your
Content-Security-Policyheader, as the modern replacement for
X-Frame-Options(though both should be included since not all browsers support it yet, see this).
X-Content-Type-Options: nosniffheader, to disable MIME sniffing.
X-XSS-Protection: 1; mode=block;header, for basic XSS protection in legacy browsers.
If you are using nginx, this would look something like the following:
add_header X-Frame-Options SAMEORIGIN; add_header X-Content-Type-Options nosniff; add_header X-XSS-Protection "1; mode=block"; add_header Content-Security-Policy "frame-ancestors 'self'";
For Apache, the configuration looks like:
Header set X-Frame-Options SAMEORIGIN Header set X-Content-Type-Options nosniff Header set X-XSS-Protection "1; mode=block" Header set Content-Security-Policy "frame-ancestors 'self'"
Note: In case you are already setting a
elsewhere, you should modify it to include the
instead of adding that last line.
Building From Source
Element is a modular webapp built with modern ES6 and uses a Node.js build system. Ensure you have the latest LTS version of Node.js installed.
yarn instead of
npm is recommended. Please see the Yarn install
guide if you do not have it already.
- Install or update
node.jsso that your
nodeis at least the current recommended LTS.
yarnif not present already.
- Clone the repo:
git clone https://github.com/vector-im/element-web.git.
- Switch to the element-web directory:
- Install the prerequisites:
- Configure the app by copying
config.jsonand modifying it. See the configuration docs for details.
yarn distto build a tarball to deploy. Untaring this file will give a version-specific directory containing all the files that need to go on your web server.
yarn dist is not supported on Windows, so Windows users can run
which will build all the necessary files into the
webapp directory. The version of Element
will not appear in Settings without using the dist script. You can then mount the
webapp directory on your web server to actually serve up the app, which is
entirely static content.
Running as a Desktop app
Element can also be run as a desktop app, wrapped in Electron. You can download a pre-built version from https://element.io/get-started or, if you prefer, build it yourself.
To build it yourself, follow the instructions at https://github.com/vector-im/element-desktop.
Many thanks to @aviraldg for the initial work on the Electron integration.
The configuration docs show how to override the desktop app's default settings if desired.
Element supports a variety of settings to configure default servers, behaviour, themes, etc. See the configuration docs for more details.
Some features of Element may be enabled by flags in the
Labs section of the settings.
Some of these features are described in labs.md.
Element requires the following URLs not to be cached, when/if you are serving Element from your own webserver:
/config.*.json /i18n /home /sites /index.html
We also recommend that you force browsers to re-validate any cached copy of Element on page load by configuring your
webserver to return
Cache-Control: no-cache for
/. This ensures the browser will fetch a new version of Element on
the next page load after it's been deployed. Note that this is already configured for you in the nginx config of our
Before attempting to develop on Element you must read the developer guide
also defines the design, architecture and style for Element too.
Read the Choosing an issue page for some guidance about where to start. Before starting work on a feature, it's best to ensure your plan aligns well with our vision for Element. Please chat with the team in #element-dev:matrix.org before you start so we can ensure it's something we'd be willing to merge.
You should also familiarise yourself with the "Here be Dragons" guide to the tame & not-so-tame dragons (gotchas) which exist in the codebase.
The idea of Element is to be a relatively lightweight "skin" of customisations on
top of the underlying
matrix-react-sdk provides both the
higher and lower level React components useful for building Matrix communication
apps using React.
Please note that Element is intended to run correctly without access to the public internet. So please don't depend on resources (JS libs, CSS, images, fonts) hosted by external CDNs or servers but instead please package all dependencies into Element itself.
CSS hot-reload is available as an opt-in development feature. You can enable it
by defining a
CSS_HOT_RELOAD environment variable, in a
.env file in the root
of the repository. See
.env.example for documentation and an example.
Setting up a dev environment
Much of the functionality in Element is actually in the
matrix-js-sdk modules. It is possible to set these up in a way that makes it
easy to track the
develop branches in git and to make local changes without
having to manually rebuild each time.
First clone and build
git clone https://github.com/matrix-org/matrix-js-sdk.git pushd matrix-js-sdk yarn link yarn install popd
Then similarly with
git clone https://github.com/matrix-org/matrix-react-sdk.git pushd matrix-react-sdk yarn link yarn link matrix-js-sdk yarn install popd
Clone the repo and switch to the
git clone https://github.com/vector-im/element-web.git cd element-web
Configure the app by copying
modifying it. See the configuration docs for details.
Finally, build and start Element itself:
yarn link matrix-js-sdk yarn link matrix-react-sdk yarn install yarn start
Wait a few seconds for the initial build to finish; you should see something like:
[element-js] <s> [webpack.Progress] 100% [element-js] [element-js] ℹ ｢wdm｣: 1840 modules [element-js] ℹ ｢wdm｣: Compiled successfully.
Remember, the command will not terminate since it runs the web server and rebuilds source files when they change. This development server also disables caching, so do NOT use it in production.
Open http://127.0.0.1:8080/ in your browser to see your newly built Element.
Note: The build script uses inotify by default on Linux to monitor directories
for changes. If the inotify limits are too low your build will fail silently or with
Error: EMFILE: too many open files. To avoid these issues, we recommend a watch limit
of at least
128M and instance limit around
To set a new inotify watch and instance limit, execute:
sudo sysctl fs.inotify.max_user_watches=131072 sudo sysctl fs.inotify.max_user_instances=512 sudo sysctl -p
If you wish, you can make the new limits permanent, by executing:
echo fs.inotify.max_user_watches=131072 | sudo tee -a /etc/sysctl.conf echo fs.inotify.max_user_instances=512 | sudo tee -a /etc/sysctl.conf sudo sysctl -p
When you make changes to
matrix-js-sdk they should be
automatically picked up by webpack and built.
If any of these steps error with,
file table overflow, you are probably on a mac
which has a very low limit on max open files. Run
ulimit -Sn 1024 and try again.
You'll need to do this in each new terminal you open before building Element.
Running the tests
There are a number of application-level tests in the
tests directory; these
are designed to run with Jest and JSDOM. To run them
See matrix-react-sdk for how to run the end-to-end tests.
To add a new translation, head to the translating doc.
For a developer guide, see the translating dev doc.
Issues are triaged by community members and the Web App Team, following the triage process.
We use issue labels to sort all incoming issues.