HTTP/2 302 location: /en-US/developers/ via: 1.1 google, 1.1 varnish, 1.1 varnish, 1.1 varnish content-type: text/html; charset=utf-8 cache-control: max-age=31536000 server: openresty accept-ranges: bytes age: 0 date: Wed, 08 Oct 2025 09:05:08 GMT x-served-by: cache-bfi-kbfi7400074-BFI, cache-bfi-kbfi7400069-BFI, cache-bom-vanm7210073-BOM x-cache: MISS, MISS, MISS x-cache-hits: 0, 0, 0 x-timer: S1759914308.355932,VS0,VE261 vary: Accept-Language content-length: 0 HTTP/2 200 content-encoding: gzip x-amo-request-id: 9fc405792201419d8c3d936c96f19b1e strict-transport-security: max-age=31536000 x-content-type-options: nosniff content-type: text/html; charset=utf-8 cache-control: s-maxage=0 x-frame-options: DENY server: openresty etag: W/"7b2b9aaa667d38d4f2867779b2378132" content-security-policy: form-action 'self' https://www.mozilla.org/en-US/newsletter/; default-src 'none'; connect-src 'self' https://*.google-analytics.com https://*.analytics.google.com https://*.googletagmanager.com https://www.mozilla.org/en-US/newsletter/; frame-src https://www.recaptcha.net/recaptcha/; media-src https://videos.cdn.mozilla.net; child-src https://www.recaptcha.net/recaptcha/; style-src 'unsafe-inline' https://addons.mozilla.org/static-server/; font-src 'self' https://addons.mozilla.org/static-server/; img-src 'self' blob: data: https://addons.mozilla.org/static-server/ https://addons.mozilla.org/user-media/ https://*.google-analytics.com https://*.googletagmanager.com; script-src https://*.google-analytics.com https://*.googletagmanager.com https://www.recaptcha.net/recaptcha/ https://www.gstatic.com/recaptcha/ https://www.gstatic.cn/recaptcha/ https://addons.mozilla.org/static-server/; object-src 'none'; report-uri /__cspreport__ via: 1.1 google, 1.1 varnish, 1.1 varnish, 1.1 varnish cross-origin-opener-policy: same-origin referrer-policy: same-origin accept-ranges: bytes age: 0 date: Wed, 08 Oct 2025 09:05:08 GMT x-served-by: cache-bfi-kbfi7400078-BFI, cache-bfi-kbfi7400038-BFI, cache-bom-vanm7210073-BOM x-cache: MISS, MISS, MISS x-cache-hits: 0, 0, 0 x-timer: S1759914309.629810,VS0,VE319 vary: Accept-Encoding content-length: 4039

Customize Firefox

Whether you’re new to extension development, polishing up or porting an existing extension or theme, or creating a custom enterprise solution, we’ve got the resources to support you.

Learn how to make an extension

Ready to submit or manage your extension?

Sign in to the Developer Hub to submit or manage extensions and themes.

Register for a developer account or log in to the Developer Hub

Get involved

Connect with thousands of developers and discover more ways you can contribute to the extension ecosystem.

Learn more about the developer community

Connect with us

• Matrix
• Community forum

Extensions Developers Newsletter

Stay up-to-date on news and events for Firefox extension developers.

Email Address

I’m okay with Mozilla handling my info as explained in this Privacy Notice.

Sign Up

Thanks!

If you haven’t previously confirmed a subscription to a Mozilla-related newsletter you may have to do so. Please check your inbox or your spam filter for an email from us.