{"id":78448,"date":"2025-02-25T06:00:00","date_gmt":"2025-02-25T14:00:00","guid":{"rendered":"https:\/\/blog.mozilla.org\/?p=78448"},"modified":"2025-04-15T15:42:36","modified_gmt":"2025-04-15T22:42:36","slug":"firefox-manifest-v3-adblockers","status":"publish","type":"post","link":"https:\/\/blog.mozilla.org\/en\/firefox\/firefox-manifest-v3-adblockers\/","title":{"rendered":"Mozilla\u2019s approach to Manifest V3: What\u2019s different and why it matters for extension users"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" loading=\"lazy\" width=\"1024\" height=\"576\" src=\"https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2023\/12\/FX_Distilled_WorldofExtensions_blogheader_1920x1080_blue-1024x576.jpg\" alt=\"\" class=\"wp-image-73806\" srcset=\"https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2023\/12\/FX_Distilled_WorldofExtensions_blogheader_1920x1080_blue-1024x576.jpg 1024w, https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2023\/12\/FX_Distilled_WorldofExtensions_blogheader_1920x1080_blue-300x169.jpg 300w, https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2023\/12\/FX_Distilled_WorldofExtensions_blogheader_1920x1080_blue-768x432.jpg 768w, https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2023\/12\/FX_Distilled_WorldofExtensions_blogheader_1920x1080_blue-1536x864.jpg 1536w, https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2023\/12\/FX_Distilled_WorldofExtensions_blogheader_1920x1080_blue-1000x562.jpg 1000w, https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2023\/12\/FX_Distilled_WorldofExtensions_blogheader_1920x1080_blue-1279x719.jpg 1279w, https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2023\/12\/FX_Distilled_WorldofExtensions_blogheader_1920x1080_blue.jpg 1921w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Extensions are like apps for your browser, letting you customize and enhance your online experience. Nearly half of all Firefox users have installed at least one extension, from <a href=\"https:\/\/addons.mozilla.org\/en-US\/firefox\/collections\/4757633\/privacy-matters\/\" target=\"_blank\" rel=\"noreferrer noopener\">privacy tools<\/a> to <a href=\"https:\/\/addons.mozilla.org\/blog\/supercharge-your-productivity-with-a-browser-extension\/\">productivity boosters<\/a>.<\/p>\n\n\n\n<p>To build these extensions, developers rely on a platform called WebExtensions, which provides <a href=\"https:\/\/developer.mozilla.org\/en-US\/docs\/Glossary\/API\" target=\"_blank\" rel=\"noreferrer noopener\">APIs<\/a><strong> <\/strong>\u2014 the tools that allow extensions to interact with web pages and browser features. Right now, all major browsers \u2014 including Firefox, Chrome and Safari \u2014 are implementing the latest version of this platform, Manifest V3. But different browsers are taking different approaches, and those differences affect which extensions you can use.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Firefox&#8217;s approach to Manifest V3 is shaped by our mission<\/h2>\n\n\n\n<p>Principle 5 of the <a href=\"https:\/\/www.mozilla.org\/en-US\/about\/manifesto\/\" target=\"_blank\" rel=\"noreferrer noopener\">Mozilla Manifesto<\/a> states: <em>Individuals must have the ability to shape the internet and their own experiences on it.<\/em> That philosophy drives our approach to Manifest V3.<\/p>\n\n\n\n<ul>\n<li><strong>More creative possibilities for <\/strong><a href=\"https:\/\/blog.mozilla.org\/en\/mozilla\/how-to-get-started-open-source-development\/\"><strong>developers<\/strong><\/a> \u2014 We\u2019ve introduced a broader range of APIs, including new AI functionality that allows extensions to run offline machine learning tasks directly in the browser.<\/li>\n\n\n\n<li><strong>Support for both Manifest V2 and V3<\/strong> \u2014 While some browsers are phasing out Manifest V2 entirely, Firefox is keeping it alongside Manifest V3. More tools for developers means more choice and innovation for users.<\/li>\n<\/ul>\n\n\n\n<p>Giving people choice and control on the internet has always been core to Mozilla. It\u2019s all about making sure users have the freedom to shape their own experiences online.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">No limits on your extensions with Firefox<\/h2>\n\n\n\n<p>Google began phasing out Manifest V2 last year and plans to end support for extensions built on it by mid-2025. That change has real consequences: Chrome users are already losing access to <a href=\"https:\/\/addons.mozilla.org\/en-US\/firefox\/addon\/ublock-origin\/\" target=\"_blank\" rel=\"noreferrer noopener\">uBlock Origin<\/a>, one of the most popular ad blockers, because it relies on a Manifest V2 feature called <em><strong>blockingWebRequest<\/strong><\/em>.<\/p>\n\n\n\n<p>Google\u2019s approach replaces <em>blockingWebRequest<\/em> with <em>declarativeNetRequest<\/em>, which limits how extensions can filter content. Since APIs<strong> <\/strong>define what extensions can and can\u2019t do inside a browser, restricting certain APIs can limit what types of extensions are possible.<\/p>\n\n\n\n<p>Firefox, however, will continue supporting both <em>blockingWebRequest<\/em> and <em>declarativeNetRequest<\/em> \u2014 giving developers more flexibility and <strong>keeping powerful privacy tools available to users<\/strong>. We\u2019ll keep you updated on what\u2019s next for extensions in Firefox. In the meantime, check out <a href=\"https:\/\/addons.mozilla.org\" target=\"_blank\" rel=\"noreferrer noopener\">addons.mozilla.org<\/a> to explore thousands of ways to customize your Firefox.<\/p>\n\n\n\n<a class=\"ft-c-inline-cta\" href=\" https:\/\/www.firefox.com\/browsers\/mobile\/app\/?product=firefox&#038;campaign=fx146blog\">\n  <div class=\"ft-c-inline-cta__media\">\n  <img loading=\"lazy\" width=\"800\" height=\"800\" src=\"https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2021\/10\/Visual-Guidelines-800x800.png\" class=\"attachment-1x1 size-1x1\" alt=\"\" decoding=\"async\" srcset=\"https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2021\/10\/Visual-Guidelines-800x800.png 800w, https:\/\/blog.mozilla.org\/wp-content\/blogs.dir\/278\/files\/2021\/10\/Visual-Guidelines-150x150.png 150w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>  <\/div>\n  <div class=\"ft-c-inline-cta__content\">\n     <h3>Take Firefox with you<\/h3>      <span>Download Firefox mobile<\/span>   <\/div>\n<\/a>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Extensions are like apps for your browser, letting you customize and enhance your online experience. Nearly half of all Firefox users have installed at least one extension, from privacy tools to productivity boosters. To build these extensions, developers rely on a platform called WebExtensions, which provides APIs \u2014 the tools that allow extensions to interact [&hellip;]<\/p>\n","protected":false},"author":1889,"featured_media":73806,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[462006,30,464325],"tags":[4708],"coauthors":[464310,464309],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Mozilla\u2019s approach to Manifest V3: What\u2019s different and why it matters for extension users<\/title>\n<meta name=\"description\" content=\"While some browsers are phasing out Manifest V2 entirely, Firefox is keeping it alongside Manifest V3 \u2014 ensuring powerful privacy tools remain available to users.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" 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