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    4.6.3 • Public • Published

    Browserslist Cult Of Martians

    Browserslist logo by Anton Lovchikov

    The config to share target browsers and Node.js versions between different front-end tools. It is used in:

    Browserslist Example shows how every tool uses Browserslist. All tools will find target browsers automatically, when you add the following to package.json:

      "browserslist": [
        "last 1 version",
        "> 1%",
        "maintained node versions",
        "not dead"

    Or in .browserslistrc config:

    # Browsers that we support
    last 1 version
    > 1%
    maintained node versions
    not dead

    Developers set versions list in queries like last 2 version to be free from updating versions manually. Browserslist will use Can I Use data for this queries.

    Browserslist will take queries from tool option, browserslist config, .browserslistrc config, browserslist section in package.json or environment variables.

    You can test Browserslist queries in online demo.

    Sponsored by Evil Martians


    • browserslist-ga downloads your website browsers statistics to use it in > 0.5% in my stats query.
    • browserslist-useragent-regexp compiles Browserslist query to a RegExp to test browser useragent.
    • browserslist-useragent-ruby is a Ruby library to checks browser by user agent string to match Browserslist.
    • browserslist-browserstack runs BrowserStack tests for all browsers in Browserslist config.
    • caniuse-api returns browsers which support some specific feature.
    • Run npx browserslist in your project directory to see project’s target browsers. This CLI tool is built-in and available in any project with Autoprefixer.

    Best Practices

    • Select browsers directly (last 2 Chrome versions) only if you are making a web app for a kiosk with one browser. There are a lot of browsers on the market. If you are making general web app you should respect browsers diversity.

    • There is a defaults query, which gives a reasonable configuration for most users:

        "browserslist": [
    • If you want to change the default set of browsers we recommend to combine last 1 version, not dead with > 0.2% (or > 1% in US, > 1% in my stats). last n versions adds too many dead browsers and does not add popular old versions. Choosing a percentage above 0.2% will in the long run make popular browsers even more popular. We might run into a monopoly and stagnation situation, as we had with Internet Explorer 6. Please use this setting with caution.

    • Don’t remove browsers just because you don’t know them. Opera Mini has 100 million users in Africa and it is more popular in the global market than Microsoft Edge. Chinese QQ Browsers has more market share than Firefox and desktop Safari combined.


    Browserslist will use browsers and Node.js versions query from one of this sources:

    1. browserslist key in package.json file in current or parent directories. We recommend this way.
    2. .browserslistrc config file in current or parent directories.
    3. browserslist config file in current or parent directories.
    4. BROWSERSLIST environment variable.
    5. If the above methods did not produce a valid result Browserslist will use defaults: > 0.5%, last 2 versions, Firefox ESR, not dead.

    Query Composition

    An or combiner can use the keyword or as well as ,. last 1 version or > 1% is equal to last 1 version, > 1%.

    and query combinations are also supported to perform an intersection of the previous query: last 1 version and > 1%.

    There is 3 different ways to combine queries as depicted below. First you start with a single query and then we combine the queries to get our final list.

    Obviously you can not start with a not combiner, since the is no left-hand side query to combine it with.

    Query combiner type Illustration Example
    or/ , combiner
    Union of queries '> .5% or last 2 versions'
    '> .5%, last 2 versions'
    and combiner
    intersection of queries '> .5% and last 2 versions'
    not combiner
    (relative complement)
    Relative complement of queries '> .5% and not last 2 versions'
    '> .5% or not last 2 versions'
    '> .5%, not last 2 versions'

    A quick way to test your query is to do npx browserslist '> 0.5%, not IE 11' in your terminal.

    Full List

    You can specify the browser and Node.js versions by queries (case insensitive):

    • > 5%: browsers versions selected by global usage statistics. >=, < and <= work too.
    • > 5% in US: uses USA usage statistics. It accepts two-letter country code.
    • > 5% in alt-AS: uses Asia region usage statistics. List of all region codes can be found at caniuse-lite/data/regions.
    • > 5% in my stats: uses custom usage data.
    • cover 99.5%: most popular browsers that provide coverage.
    • cover 99.5% in US: same as above, with two-letter country code.
    • cover 99.5% in my stats: uses custom usage data.
    • maintained node versions: all Node.js versions, which are still maintained by Node.js Foundation.
    • node 10 and node 10.4: selects latest Node.js 10.x.x or 10.4.x release.
    • current node: Node.js version used by Browserslist right now.
    • extends browserslist-config-mycompany: take queries from browserslist-config-mycompany npm package.
    • ie 6-8: selects an inclusive range of versions.
    • Firefox > 20: versions of Firefox newer than 20. >=, < and <= work too. It also works with Node.js.
    • iOS 7: the iOS browser version 7 directly.
    • Firefox ESR: the latest [Firefox ESR] version.
    • unreleased versions or unreleased Chrome versions: alpha and beta versions.
    • last 2 major versions or last 2 iOS major versions: all minor/patch releases of last 2 major versions.
    • since 2015 or last 2 years: all versions released since year 2015 (also since 2015-03 and since 2015-03-10).
    • dead: browsers from last 2 version query, but with less than 0.5% in global usage statistics and without official support or updates for 24 months. Right now it is IE 10, IE_Mob 10, BlackBerry 10, BlackBerry 7, and OperaMobile 12.1.
    • last 2 versions: the last 2 versions for each browser.
    • last 2 Chrome versions: the last 2 versions of Chrome browser.
    • defaults: Browserslist’s default browsers (> 0.5%, last 2 versions, Firefox ESR, not dead).
    • not ie <= 8: exclude browsers selected by previous queries.

    You can add not to any query.


    Run npx browserslist in project directory to see what browsers was selected by your queries.

    $ npx browserslist
    and_chr 61
    and_ff 56
    and_qq 1.2
    and_uc 11.4
    android 56
    baidu 7.12
    bb 10
    chrome 62
    edge 16
    firefox 56
    ios_saf 11
    opera 48
    safari 11
    samsung 5


    Names are case insensitive:

    • Android for Android WebView.
    • Baidu for Baidu Browser.
    • BlackBerry or bb for Blackberry browser.
    • Chrome for Google Chrome.
    • ChromeAndroid or and_chr for Chrome for Android
    • Edge for Microsoft Edge.
    • Electron for Electron framework. It will be converted to Chrome version.
    • Explorer or ie for Internet Explorer.
    • ExplorerMobile or ie_mob for Internet Explorer Mobile.
    • Firefox or ff for Mozilla Firefox.
    • FirefoxAndroid or and_ff for Firefox for Android.
    • iOS or ios_saf for iOS Safari.
    • Node for Node.js.
    • Opera for Opera.
    • OperaMini or op_mini for Opera Mini.
    • OperaMobile or op_mob for Opera Mobile.
    • QQAndroid or and_qq for QQ Browser for Android.
    • Safari for desktop Safari.
    • Samsung for Samsung Internet.
    • UCAndroid or and_uc for UC Browser for Android.
    • kaios for KaiOS Browser.


    If you want to reduce config files in project root, you can specify browsers in package.json with browserslist key:

      "private": true,
      "dependencies": {
        "autoprefixer": "^6.5.4"
      "browserslist": [
        "last 1 version",
        "> 1%",
        "IE 10"

    Config File

    Browserslist config should be named .browserslistrc or browserslist and have browsers queries split by a new line. Comments starts with # symbol:

    # Browsers that we support
    last 1 version
    > 1%
    IE 10 # sorry

    Browserslist will check config in every directory in path. So, if tool process app/styles/main.css, you can put config to root, app/ or app/styles.

    You can specify direct path in BROWSERSLIST_CONFIG environment variables.

    Shareable Configs

    You can use the following query to reference an exported Browserslist config from another package:

      "browserslist": [
        "extends browserslist-config-mycompany"

    For security reasons, external configuration only supports packages that have the browserslist-config- prefix. npm scoped packages are also supported, by naming or prefixing the module with @scope/browserslist-config, such as @scope/browserslist-config or @scope/browserslist-config-mycompany.

    If you don’t accept Browserslist queries from users, you can disable the validation by using the dangerousExtend option:

    browserslist(queries, { path, dangerousExtend: true })

    Because this uses npm's resolution, you can also reference specific files in a package:

      "browserslist": [
        "extends browserslist-config-mycompany/desktop",
        "extends browserslist-config-mycompany/mobile"

    When writing a shared Browserslist package, just export an array. browserslist-config-mycompany/index.js:

    module.exports = [
      'last 1 version',
      '> 1%',
      'ie 10'

    Environment Variables

    If some tool use Browserslist inside, you can change browsers settings by environment variables:

    • BROWSERSLIST with browsers queries.

      BROWSERSLIST="> 5%" gulp css
    • BROWSERSLIST_CONFIG with path to config file.

      BROWSERSLIST_CONFIG=./config/browserslist gulp css
    • BROWSERSLIST_ENV with environments string.

      BROWSERSLIST_ENV="development" gulp css
    • BROWSERSLIST_STATS with path to the custom usage data for > 1% in my stats query.

      BROWSERSLIST_STATS=./config/usage_data.json gulp css
    • BROWSERSLIST_DISABLE_CACHE if you want to disable config reading cache.



    You can also specify different browser queries for various environments. Browserslist will choose query according to BROWSERSLIST_ENV or NODE_ENV variables. If none of them is declared, Browserslist will firstly look for production queries and then use defaults.

    In package.json:

      "browserslist": {
        "production": [
          "> 1%",
          "ie 10"
        "modern": [
          "last 1 chrome version",
          "last 1 firefox version"
        "ssr": [
          "node 12"

    In .browserslistrc config:

    > 1%
    ie 10
    last 1 chrome version
    last 1 firefox version
    node 12

    Custom Usage Data

    If you have a website, you can query against the usage statistics of your site. browserslist-ga will ask access to Google Analytics and then generate browserslist-stats.json:

    npx browserslist-ga

    Of course, you can generate usage statistics file by any other method. File format should be like:

      "ie": {
        "6": 0.01,
        "7": 0.4,
        "8": 1.5
      "chrome": {},}

    Note that you can query against your custom usage data while also querying against global or regional data. For example, the query > 1% in my stats, > 5% in US, 10% is permitted.

    JS API

    const browserslist = require('browserslist')
    // Your CSS/JS build tool code
    function process (source, opts) {
      const browsers = browserslist(opts.overrideBrowserslist, {
        stats: opts.stats,
        path:  opts.file,
        env:   opts.env
      // Your code to add features for selected browsers

    Queries can be a string "> 1%, IE 10" or an array ['> 1%', 'IE 10'].

    If a query is missing, Browserslist will look for a config file. You can provide a path option (that can be a file) to find the config file relatively to it.


    • path: file or a directory path to look for config file. Default is ..
    • env: what environment section use from config. Default is production.
    • stats: custom usage statistics data.
    • config: path to config if you want to set it manually.
    • ignoreUnknownVersions: do not throw on direct query (like ie 12). Default is false.
    • dangerousExtend: Disable security checks for extend query. Default is false.
    • mobileToDesktop: Use desktop browsers if Can I Use doesn’t have data about this mobile version. For instance, Browserslist will return chrome 20 on and_chr 20 query (Can I Use has only data only about latest versions of mobile browsers). Default is false.

    For non-JS environment and debug purpose you can use CLI tool:

    browserslist "> 1%, IE 10"


    You can get total users coverage for selected browsers by JS API:

    browserslist.coverage(browserslist('> 1%'))
    //=> 81.4
    browserslist.coverage(browserslist('> 1% in US'), 'US')
    //=> 83.1
    browserslist.coverage(browserslist('> 1% in my stats'), 'my stats')
    //=> 83.1
    browserslist.coverage(browserslist('> 1% in my stats', { stats }), stats)
    //=> 82.2

    Or by CLI:

    $ browserslist --coverage "> 1%"
    These browsers account for 81.4% of all users globally
    $ browserslist --coverage=US "> 1% in US"
    These browsers account for 83.1% of all users in the US
    $ browserslist --coverage "> 1% in my stats"
    These browsers account for 83.1% of all users in custom statistics
    $ browserslist --coverage "> 1% in my stats" --stats=./stats.json
    These browsers account for 83.1% of all users in custom statistics


    Browserslist caches the configuration it reads from package.json and browserslist files, as well as knowledge about the existence of files, for the duration of the hosting process.

    To clear these caches, use:


    To disable the caching altogether, set the BROWSERSLIST_DISABLE_CACHE environment variable.

    Security Contact

    To report a security vulnerability, please use the Tidelift security contact. Tidelift will coordinate the fix and disclosure.


    npm i browserslist@4.6.3





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