MetaMask supports Firefox, Google Chrome, and Chromium-based browsers. We recommend using the latest available browser version.
To learn how to develop MetaMask-compatible applications, visit our Developer Docs.
To learn how to contribute to the MetaMask project itself, visit our Internal Docs.
nvm usewill automatically choose the right node version for you.
yarn setup(not the usual install command)
INFURA_PROJECT_IDvalue with your own personal Infura Project ID.
SEGMENT_WRITE_KEYSegment write key, see Developing on MetaMask - Segment.
SENTRY_DSNSentry Dsn, see Developing on MetaMask - Sentry.
PASSWORDvalue with your development wallet password to avoid entering it each time you open the app.
yarn startto run dev mode.
Uncompressed builds can be found in
/dist, compressed builds can be found in
/builds once they're built.
See the build system readme for build system usage information.
To start a development build (e.g. with logging and file watching) run
To start the React DevTools, run
yarn devtools:react with a development build installed in a browser. This will open in a separate window; no browser extension is required.
To start the Redux DevTools Extension:
yarn global add remotedev-server)
8000, secure connection checkbox unchecked).
Then run the command
yarn devtools:redux with a development build installed in a browser. This will enable you to use the Redux DevTools extension to inspect MetaMask.
To create a development build and run both of these tools simultaneously, run
This test site can be used to execute different user flows.
Run unit tests and the linter with
yarn test. To run just unit tests, run
You can run the linter by itself with
yarn lint, and you can automatically fix some lint problems with
yarn lint:fix. You can also run these two commands just on your local changes to save time with
yarn lint:changed and
yarn lint:changed:fix respectively.
Our e2e test suite can be run on either Firefox or Chrome. In either case, start by creating a test build by running
Firefox e2e tests can be run with
Chrome e2e tests can be run with
yarn test:e2e:chrome. The
chromedriver package major version must match the major version of your local Chrome installation. If they don't match, update whichever is behind before running Chrome e2e tests.
Single e2e tests can be run with
yarn test:e2e:single test/e2e/tests/TEST_NAME.spec.js along with the options below.
--browser Set the browser used; either 'chrome' or 'firefox'. --leave-running Leaves the browser running after a test fails, along with anything else that the test used (ganache, the test dapp, etc.). --retries Set how many times the test should be retried upon failure. Default is 0.
An example for running
account-details testcase with chrome and leaving the browser open would be:
yarn test:e2e:single test/e2e/tests/account-details.spec.js --browser=chrome --leave-running
Whenever you change dependencies (adding, removing, or updating, either in
yarn.lock), there are various files that must be kept up-to-date.
yarn setupagain after your changes to ensure
yarn.lockhas been properly updated.
yarn yarn-deduplicateto remove duplicate dependencies from the lockfile.
yarn allow-scripts autoto update the
allow-scriptsconfiguration automatically. This config determines whether the package's install/postinstall scripts are allowed to run. Review each new package to determine whether the install script needs to run or not, testing if necessary.
yarn allow-scripts autowill behave inconsistently on different platforms. macOS and Windows users may see extraneous changes relating to optional dependencies.
yarn lavamoat:autoto update these files, but there can be devils in the details. Continue reading for more information.
lavamoat/browserify/*/policy.json), which are re-generated using
lavamoat/build-system/policy.json), which is re-generated using
yarn lavamoat:autowill behave inconsistently on different platforms. macOS and Windows users may see extraneous changes relating to optional dependencies.