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, Safari, and Edge on desktop OSes
- 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, Firefox, and Safari
- 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 copy of Element, the quickest bet is to use a pre-built released version of Element:
- Download the latest version from https://github.com/vector-im/element-web/releases
- Untar the tarball on your web server
- Move (or symlink) the
element-x.x.xdirectory to an appropriate name
- Configure the correct caching headers in your webserver (see below)
- If desired, copy
config.jsonand edit it as desired. See the configuration docs for details.
- Enter the URL into your browser and log into Element!
Releases are signed using gpg and the OpenPGP standard, and can be checked against the public key located at https://packages.riot.im/element-release-key.asc.
Note that for the security of your chats will need to serve Element over HTTPS. Major browsers also do not allow you to use VoIP/video chats over HTTP, as WebRTC is only usable over HTTPS. There are some exceptions like when using localhost, which is considered a secure context and thus allowed.
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 'none'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 'none'";
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 v10.x.
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.
Other options for running as a desktop app:
- @asdf:matrix.org points out that you can use nativefier and it just works(tm)
yarn global add nativefier nativefier https://app.element.io/
The configuration docs show how to override the desktop app's default settings if desired.
Running from Docker
The Docker image can be used to serve element-web as a web server. The easiest way to use it is to use the prebuilt image:
docker run -p 80:80 vectorim/element-web
To supply your own custom
config.json, map a volume to
/app/config.json. For example,
if your custom config was located at
/etc/element-web/config.json then your Docker command
docker run -p 80:80 -v /etc/element-web/config.json:/app/config.json vectorim/element-web
To build the image yourself:
git clone https://github.com/vector-im/element-web.git element-web cd element-web git checkout master docker build .
If you're building a custom branch, or want to use the develop branch, check out the appropriate element-web branch and then run:
docker build -t \ --build-arg USE_CUSTOM_SDKS=true \ --build-arg REACT_SDK_REPO="https://github.com/matrix-org/matrix-react-sdk.git" \ --build-arg REACT_SDK_BRANCH="develop" \ --build-arg JS_SDK_REPO="https://github.com/matrix-org/matrix-js-sdk.git" \ --build-arg JS_SDK_BRANCH="develop" \ .
Running in Kubernetes
The provided element-web docker image can also be run from within a Kubernetes cluster. See the Kubernetes example for more details.
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
Before attempting to develop on Element you must read the developer guide
also defines the design, architecture and style for Element too.
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.
After creating a new component you must run
yarn reskindex to regenerate
component-index.js for the app (used in future for skinning).
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
Finally, build and start Element itself:
git clone https://github.com/vector-im/element-web.git cd element-web yarn link matrix-js-sdk yarn link matrix-react-sdk yarn install yarn reskindex 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.
Configure the app by copying
modifying it. See the configuration docs for details.
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 you add or remove any components from the Element skin, you will need to rebuild
the skin's index by running,
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 in a browser instance under the control of
karma. To run them:
- Make sure you have Chrome installed (a recent version, like 59)
- Make sure you have
matrix-react-sdkinstalled and built, as above
The above will run the tests under Chrome in a
You can also tell karma to run the tests in a loop (every time the source
changes), in an instance of Chrome on your desktop, with
yarn test-multi. This also gives you the option of running the tests in 'debug'
mode, which is useful for stepping through the tests in the developer tools.
See matrix-react-sdk 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.
We strive to completely cover all applicable issues with these core labels:
Type — Every issue is assigned a type:
- T-Defect: Bugs, crashes, hangs, vulnerabilities, or other reported problems
- T-Enhancement: New features, changes in functionality, performance boosts, user-facing improvements
- T-Task: Refactoring, enabling or disabling functionality, other engineering tasks
- T-Other: Questions, user support, anything else
Severity — All issues labeled
T-Defectare also assigned a severity:
- S-Critical: Prevents work, causes data loss, affects many users, and/or has no workaround
- S-Major: Severely degrades major functionality or product features, with no satisfactory workaround
- S-Minor: Impairs non-critical functionality, or suitable workarounds exist
- S-Tolerable: Purely cosmetic or low / no impact to users
Prevalence — All issues labeled
T-Defectare also assigned a prevalence:
- P-High: Affects most users regularly or impacts most users' first experience (e.g. registration)
- P-Medium: Affects some users regularly or most users rarely
- P-Low: Most users are unlikely to come across this or it is a corner case
This label may also be used for other types of issues.
Area — Most issues are assigned one or several "areas" using one of the many
A-prefixed labels, e.g.
A-Spaces. Each area label maps to a group of features or portion of the UI surface in the app.
The Priority label is now deprecated. Defects will now be classed based on their severity and prevalence:
|Labels||Equivalent priority||What it means|
|S‑Critical and P‑High
S‑Critical and P‑Medium
S‑Major and P‑High
|P1||These issues should be worked on in this sprint or next sprint. If the backlog of issues is too long, we should reevaluate why the bugs are not caught earlier.|
|S‑Critical and P‑Low
S‑Major and P‑Medium
S‑Minor and P‑High
|P2||When all the highest priority bugs are done, this is the next set to tackle. Ideally we should be fixing a few issues from this group every week.|
|S‑Major and P‑Low
S‑Minor and P‑Medium
S‑Tolerable and P‑High
|P3||These issues are wishful thinking for now. We hope to get to them one day, but they are low priority. There are likely to be some good new contributor issues in here.|
|S‑Minor and P‑Low
S‑Tolerable and P‑Medium
S‑Minor and P‑Low
|P4 and P5||These issues are unlikely to be actively looked at by the webapp team, but may be picked up by community.|
Other common labels
We have a handful of other labels which are added on an as-needed basis, and not expected to be exhaustive:
Exceptions — Special flags for issues and pull requests:
Sponsored — Used internally by Element to denote issues with external funding
Ad hoc labels (
We have reserved the
Z- prefix for ad hoc labels.
Any member of the core team is welcome to create labels beginning with
any purpose, such as tracking personal areas of interest or providing a common
way to label cross-repo initiatives. The prefix avoids interference with the
project's main labels.