# MetaMask Browser Extension
Hey! We are hiring a Senior Mobile Engineer! Apply here: https://boards.greenhouse.io/consensys/jobs/1990589
---
[](https://circleci.com/gh/MetaMask/metamask-extension) [](https://coveralls.io/github/MetaMask/metamask-extension?branch=master)
You can find the latest version of MetaMask on [our official website ](https://metamask.io/ ). For help using MetaMask, visit our [User Support Site ](https://metamask.zendesk.com/hc/en-us ).
MetaMask supports Firefox, Google Chrome, and Chromium-based browsers. We recommend using the latest available browser version.
For up to the minute news, follow our [Twitter ](https://twitter.com/metamask_io ) or [Medium ](https://medium.com/metamask ) pages.
To learn how to develop MetaMask-compatible applications, visit our [Developer Docs ](https://metamask.github.io/metamask-docs/ ).
To learn how to contribute to the MetaMask project itself, visit our [Internal Docs ](https://github.com/MetaMask/metamask-extension/tree/develop/docs ).
## Building locally
Switch from `npm` to `yarn` (#6843)
As a solution to the constant lockfile churn issues we've had with
`npm`, the project now uses `yarn` to manage dependencies.
The `package-lock.json` file has been replaced with `yarn.lock`, which
was created using `yarn import`. It should approximate the contents of
`package-lock.json` fairly well, though there may be some changes due to
deduplication. The codeowners file has been updated to reference this
new lockfile.
All documentation and npm scripts have been updated to reference `yarn`
rather than `npm`. Note that running scripts using `npm run` still works
fine, but it seemed better to switch those to `yarn` as well to avoid
confusion.
The `npm-audit` Bash script has been replaced with `yarn-audit`. The
output of `yarn audit` is a bit different than `npm audit` in that it
returns a bitmask to describe which severity issues were found. This
made it simpler to check the results directly from the Bash script, so
the associated `npm-audit-check.js` script was no longer required. The
output should be exactly the same, and the information is still sourced
from the same place (the npm registry).
The new `yarn-audit` script does have an external dependency: `jq`.
However, `jq` is already assumed to be present by another CI script, and
is present on all CI images we use. `jq` was not added to `package.json`
as a dependency because there is no official package on the npm
registry, just wrapper scripts. We don't need it anywhere exept on CI
anyway.
The section in `CONTRIBUTING` about how to develop inside the
`node_modules` folder was removed, as the advice was a bit dated, and
wasn't specific to this project anyway.
5 years ago
- Install [Node.js ](https://nodejs.org ) version 10
- If you are using [nvm ](https://github.com/creationix/nvm#installation ) (recommended) running `nvm use` will automatically choose the right node version for you.
Switch from `npm` to `yarn` (#6843)
As a solution to the constant lockfile churn issues we've had with
`npm`, the project now uses `yarn` to manage dependencies.
The `package-lock.json` file has been replaced with `yarn.lock`, which
was created using `yarn import`. It should approximate the contents of
`package-lock.json` fairly well, though there may be some changes due to
deduplication. The codeowners file has been updated to reference this
new lockfile.
All documentation and npm scripts have been updated to reference `yarn`
rather than `npm`. Note that running scripts using `npm run` still works
fine, but it seemed better to switch those to `yarn` as well to avoid
confusion.
The `npm-audit` Bash script has been replaced with `yarn-audit`. The
output of `yarn audit` is a bit different than `npm audit` in that it
returns a bitmask to describe which severity issues were found. This
made it simpler to check the results directly from the Bash script, so
the associated `npm-audit-check.js` script was no longer required. The
output should be exactly the same, and the information is still sourced
from the same place (the npm registry).
The new `yarn-audit` script does have an external dependency: `jq`.
However, `jq` is already assumed to be present by another CI script, and
is present on all CI images we use. `jq` was not added to `package.json`
as a dependency because there is no official package on the npm
registry, just wrapper scripts. We don't need it anywhere exept on CI
anyway.
The section in `CONTRIBUTING` about how to develop inside the
`node_modules` folder was removed, as the advice was a bit dated, and
wasn't specific to this project anyway.
5 years ago
- Install [Yarn ](https://yarnpkg.com/en/docs/install )
- Install dependencies: `yarn`
- Build the project to the `./dist/` folder with `yarn dist` .
- Optionally, to start a development build (e.g. with logging and file watching) run `yarn start` instead.
- To start the [React DevTools ](https://github.com/facebook/react-devtools ) and [Redux DevTools Extension ](http://extension.remotedev.io )
Switch from `npm` to `yarn` (#6843)
As a solution to the constant lockfile churn issues we've had with
`npm`, the project now uses `yarn` to manage dependencies.
The `package-lock.json` file has been replaced with `yarn.lock`, which
was created using `yarn import`. It should approximate the contents of
`package-lock.json` fairly well, though there may be some changes due to
deduplication. The codeowners file has been updated to reference this
new lockfile.
All documentation and npm scripts have been updated to reference `yarn`
rather than `npm`. Note that running scripts using `npm run` still works
fine, but it seemed better to switch those to `yarn` as well to avoid
confusion.
The `npm-audit` Bash script has been replaced with `yarn-audit`. The
output of `yarn audit` is a bit different than `npm audit` in that it
returns a bitmask to describe which severity issues were found. This
made it simpler to check the results directly from the Bash script, so
the associated `npm-audit-check.js` script was no longer required. The
output should be exactly the same, and the information is still sourced
from the same place (the npm registry).
The new `yarn-audit` script does have an external dependency: `jq`.
However, `jq` is already assumed to be present by another CI script, and
is present on all CI images we use. `jq` was not added to `package.json`
as a dependency because there is no official package on the npm
registry, just wrapper scripts. We don't need it anywhere exept on CI
anyway.
The section in `CONTRIBUTING` about how to develop inside the
`node_modules` folder was removed, as the advice was a bit dated, and
wasn't specific to this project anyway.
5 years ago
alongside the app, use `yarn start:dev` .
- React DevTools will open in a separate window; no browser extension is required
- Redux DevTools will need to be installed as a browser extension. Open the Redux Remote Devtools to access Redux state logs. This can be done by either right clicking within the web browser to bring up the context menu, expanding the Redux DevTools panel and clicking Open Remote DevTools OR clicking the Redux DevTools extension icon and clicking Open Remote DevTools.
- You will also need to check the "Use custom (local) server" checkbox in the Remote DevTools Settings, using the default server configuration (host `localhost` , port `8000` , secure connection checkbox unchecked)
Uncompressed builds can be found in `/dist` , compressed builds can be found in `/builds` once they're built.
## Contributing
### Running Tests
Switch from `npm` to `yarn` (#6843)
As a solution to the constant lockfile churn issues we've had with
`npm`, the project now uses `yarn` to manage dependencies.
The `package-lock.json` file has been replaced with `yarn.lock`, which
was created using `yarn import`. It should approximate the contents of
`package-lock.json` fairly well, though there may be some changes due to
deduplication. The codeowners file has been updated to reference this
new lockfile.
All documentation and npm scripts have been updated to reference `yarn`
rather than `npm`. Note that running scripts using `npm run` still works
fine, but it seemed better to switch those to `yarn` as well to avoid
confusion.
The `npm-audit` Bash script has been replaced with `yarn-audit`. The
output of `yarn audit` is a bit different than `npm audit` in that it
returns a bitmask to describe which severity issues were found. This
made it simpler to check the results directly from the Bash script, so
the associated `npm-audit-check.js` script was no longer required. The
output should be exactly the same, and the information is still sourced
from the same place (the npm registry).
The new `yarn-audit` script does have an external dependency: `jq`.
However, `jq` is already assumed to be present by another CI script, and
is present on all CI images we use. `jq` was not added to `package.json`
as a dependency because there is no official package on the npm
registry, just wrapper scripts. We don't need it anywhere exept on CI
anyway.
The section in `CONTRIBUTING` about how to develop inside the
`node_modules` folder was removed, as the advice was a bit dated, and
wasn't specific to this project anyway.
5 years ago
Run tests with `yarn test` .
Switch from `npm` to `yarn` (#6843)
As a solution to the constant lockfile churn issues we've had with
`npm`, the project now uses `yarn` to manage dependencies.
The `package-lock.json` file has been replaced with `yarn.lock`, which
was created using `yarn import`. It should approximate the contents of
`package-lock.json` fairly well, though there may be some changes due to
deduplication. The codeowners file has been updated to reference this
new lockfile.
All documentation and npm scripts have been updated to reference `yarn`
rather than `npm`. Note that running scripts using `npm run` still works
fine, but it seemed better to switch those to `yarn` as well to avoid
confusion.
The `npm-audit` Bash script has been replaced with `yarn-audit`. The
output of `yarn audit` is a bit different than `npm audit` in that it
returns a bitmask to describe which severity issues were found. This
made it simpler to check the results directly from the Bash script, so
the associated `npm-audit-check.js` script was no longer required. The
output should be exactly the same, and the information is still sourced
from the same place (the npm registry).
The new `yarn-audit` script does have an external dependency: `jq`.
However, `jq` is already assumed to be present by another CI script, and
is present on all CI images we use. `jq` was not added to `package.json`
as a dependency because there is no official package on the npm
registry, just wrapper scripts. We don't need it anywhere exept on CI
anyway.
The section in `CONTRIBUTING` about how to develop inside the
`node_modules` folder was removed, as the advice was a bit dated, and
wasn't specific to this project anyway.
5 years ago
You can also test with a continuously watching process, via `yarn watch` .
Switch from `npm` to `yarn` (#6843)
As a solution to the constant lockfile churn issues we've had with
`npm`, the project now uses `yarn` to manage dependencies.
The `package-lock.json` file has been replaced with `yarn.lock`, which
was created using `yarn import`. It should approximate the contents of
`package-lock.json` fairly well, though there may be some changes due to
deduplication. The codeowners file has been updated to reference this
new lockfile.
All documentation and npm scripts have been updated to reference `yarn`
rather than `npm`. Note that running scripts using `npm run` still works
fine, but it seemed better to switch those to `yarn` as well to avoid
confusion.
The `npm-audit` Bash script has been replaced with `yarn-audit`. The
output of `yarn audit` is a bit different than `npm audit` in that it
returns a bitmask to describe which severity issues were found. This
made it simpler to check the results directly from the Bash script, so
the associated `npm-audit-check.js` script was no longer required. The
output should be exactly the same, and the information is still sourced
from the same place (the npm registry).
The new `yarn-audit` script does have an external dependency: `jq`.
However, `jq` is already assumed to be present by another CI script, and
is present on all CI images we use. `jq` was not added to `package.json`
as a dependency because there is no official package on the npm
registry, just wrapper scripts. We don't need it anywhere exept on CI
anyway.
The section in `CONTRIBUTING` about how to develop inside the
`node_modules` folder was removed, as the advice was a bit dated, and
wasn't specific to this project anyway.
5 years ago
You can run the linter by itself with `yarn lint` .
## Architecture
[][1]
## Development
```bash
Switch from `npm` to `yarn` (#6843)
As a solution to the constant lockfile churn issues we've had with
`npm`, the project now uses `yarn` to manage dependencies.
The `package-lock.json` file has been replaced with `yarn.lock`, which
was created using `yarn import`. It should approximate the contents of
`package-lock.json` fairly well, though there may be some changes due to
deduplication. The codeowners file has been updated to reference this
new lockfile.
All documentation and npm scripts have been updated to reference `yarn`
rather than `npm`. Note that running scripts using `npm run` still works
fine, but it seemed better to switch those to `yarn` as well to avoid
confusion.
The `npm-audit` Bash script has been replaced with `yarn-audit`. The
output of `yarn audit` is a bit different than `npm audit` in that it
returns a bitmask to describe which severity issues were found. This
made it simpler to check the results directly from the Bash script, so
the associated `npm-audit-check.js` script was no longer required. The
output should be exactly the same, and the information is still sourced
from the same place (the npm registry).
The new `yarn-audit` script does have an external dependency: `jq`.
However, `jq` is already assumed to be present by another CI script, and
is present on all CI images we use. `jq` was not added to `package.json`
as a dependency because there is no official package on the npm
registry, just wrapper scripts. We don't need it anywhere exept on CI
anyway.
The section in `CONTRIBUTING` about how to develop inside the
`node_modules` folder was removed, as the advice was a bit dated, and
wasn't specific to this project anyway.
5 years ago
yarn
yarn start
```
## Build for Publishing
```bash
Switch from `npm` to `yarn` (#6843)
As a solution to the constant lockfile churn issues we've had with
`npm`, the project now uses `yarn` to manage dependencies.
The `package-lock.json` file has been replaced with `yarn.lock`, which
was created using `yarn import`. It should approximate the contents of
`package-lock.json` fairly well, though there may be some changes due to
deduplication. The codeowners file has been updated to reference this
new lockfile.
All documentation and npm scripts have been updated to reference `yarn`
rather than `npm`. Note that running scripts using `npm run` still works
fine, but it seemed better to switch those to `yarn` as well to avoid
confusion.
The `npm-audit` Bash script has been replaced with `yarn-audit`. The
output of `yarn audit` is a bit different than `npm audit` in that it
returns a bitmask to describe which severity issues were found. This
made it simpler to check the results directly from the Bash script, so
the associated `npm-audit-check.js` script was no longer required. The
output should be exactly the same, and the information is still sourced
from the same place (the npm registry).
The new `yarn-audit` script does have an external dependency: `jq`.
However, `jq` is already assumed to be present by another CI script, and
is present on all CI images we use. `jq` was not added to `package.json`
as a dependency because there is no official package on the npm
registry, just wrapper scripts. We don't need it anywhere exept on CI
anyway.
The section in `CONTRIBUTING` about how to develop inside the
`node_modules` folder was removed, as the advice was a bit dated, and
wasn't specific to this project anyway.
5 years ago
yarn dist
```
## Other Docs
- [How to add custom build to Chrome ](./docs/add-to-chrome.md )
- [How to add custom build to Firefox ](./docs/add-to-firefox.md )
- [How to add a new translation to MetaMask ](./docs/translating-guide.md )
- [Publishing Guide ](./docs/publishing.md )
- [How to port MetaMask to a new platform ](./docs/porting_to_new_environment.md )
- [How to use the TREZOR emulator ](./docs/trezor-emulator.md )
- [How to generate a visualization of this repository's development ](./development/gource-viz.sh )
[1]: http://www.nomnoml.com/#view/%5B%3Cactor%3Euser%5D%0A%0A%5Bmetamask-ui%7C%0A%20%20%20%5Btools%7C%0A%20%20%20%20%20react%0A%20%20%20%20%20redux%0A%20%20%20%20%20thunk%0A%20%20%20%20%20ethUtils%0A%20%20%20%20%20jazzicon%0A%20%20%20%5D%0A%20%20%20%5Bcomponents%7C%0A%20%20%20%20%20app%0A%20%20%20%20%20account-detail%0A%20%20%20%20%20accounts%0A%20%20%20%20%20locked-screen%0A%20%20%20%20%20restore-vault%0A%20%20%20%20%20identicon%0A%20%20%20%20%20config%0A%20%20%20%20%20info%0A%20%20%20%5D%0A%20%20%20%5Breducers%7C%0A%20%20%20%20%20app%0A%20%20%20%20%20metamask%0A%20%20%20%20%20identities%0A%20%20%20%5D%0A%20%20%20%5Bactions%7C%0A%20%20%20%20%20%5BbackgroundConnection%5D%0A%20%20%20%5D%0A%20%20%20%5Bcomponents%5D%3A-%3E%5Bactions%5D%0A%20%20%20%5Bactions%5D%3A-%3E%5Breducers%5D%0A%20%20%20%5Breducers%5D%3A-%3E%5Bcomponents%5D%0A%5D%0A%0A%5Bweb%20dapp%7C%0A%20%20%5Bui%20code%5D%0A%20%20%5Bweb3%5D%0A%20%20%5Bmetamask-inpage%5D%0A%20%20%0A%20%20%5B%3Cactor%3Eui%20developer%5D%0A%20%20%5Bui%20developer%5D-%3E%5Bui%20code%5D%0A%20%20%5Bui%20code%5D%3C-%3E%5Bweb3%5D%0A%20%20%5Bweb3%5D%3C-%3E%5Bmetamask-inpage%5D%0A%5D%0A%0A%5Bmetamask-background%7C%0A%20%20%5Bprovider-engine%5D%0A%20%20%5Bhooked%20wallet%20subprovider%5D%0A%20%20%5Bid%20store%5D%0A%20%20%0A%20%20%5Bprovider-engine%5D%3C-%3E%5Bhooked%20wallet%20subprovider%5D%0A%20%20%5Bhooked%20wallet%20subprovider%5D%3C-%3E%5Bid%20store%5D%0A%20%20%5Bconfig%20manager%7C%0A%20%20%20%20%5Brpc%20configuration%5D%0A%20%20%20%20%5Bencrypted%20keys%5D%0A%20%20%20%20%5Bwallet%20nicknames%5D%0A%20%20%5D%0A%20%20%0A%20%20%5Bprovider-engine%5D%3C-%5Bconfig%20manager%5D%0A%20%20%5Bid%20store%5D%3C-%3E%5Bconfig%20manager%5D%0A%5D%0A%0A%5Buser%5D%3C-%3E%5Bmetamask-ui%5D%0A%0A%5Buser%5D%3C%3A--%3A%3E%5Bweb%20dapp%5D%0A%0A%5Bmetamask-contentscript%7C%0A%20%20%5Bplugin%20restart%20detector%5D%0A%20%20%5Brpc%20passthrough%5D%0A%5D%0A%0A%5Brpc%20%7C%0A%20%20%5Bethereum%20blockchain%20%7C%0A%20%20%20%20%5Bcontracts%5D%0A%20%20%20%20%5Baccounts%5D%0A%20%20%5D%0A%5D%0A%0A%5Bweb%20dapp%5D%3C%3A--%3A%3E%5Bmetamask-contentscript%5D%0A%5Bmetamask-contentscript%5D%3C-%3E%5Bmetamask-background%5D%0A%5Bmetamask-background%5D%3C-%3E%5Bmetamask-ui%5D%0A%5Bmetamask-background%5D%3C-%3E%5Brpc%5D%0A
