š Introducing the MDN MCP server!
Bring MDN's docs and browser compat data straight into your AI agent or IDE for accurate, up-to-date answers about the web platform.
No more outdated guesses from training data.
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developer.mozilla.org/en-US/blog/introducing-mdn-mcp-server/
The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web. Here's how it works:
Firefox 152 landed today, and includes web platform features like:
š CSS field-sizing
š Notification actions
š unadjustedMovement pointer locks
š getAnimations() pseudoElement option
ā¦and more!
developer.mozilla.org/en-US/docs/M...
š¦ Firefox 150: <img sizes="auto"> is now supported.
Lazy-loaded images use their calculated layout size to select from srcset ā no more duplicating media queries in HTML.
Read Now š
developer.mozilla.org/en-US/docs/...
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Ever wish HTTP status codes were easier to remember? š¼ļø
Check out this MDN cheatsheet that pairs each status code with an emoji to help you visualize what each one means, from 200 OK ā to 418 Iām a teapot š«
Check it out š
š¦ New in Firefox 150: the revert-rule CSS keyword.
Make a property behave as if the current rule didn't exist, letting a value from another matching rule take effect instead.
Read Now š
developer.mozilla.org/en-US/docs/...
š¦ Firefox 150: color-mix() now accepts more than two colors at once.
Mix any number of colors in a single declaration ā no more nesting multiple calls.
Read Now š
developer.mozilla.org/en-US/docs/...
š¦ Firefox 150: light-dark() now accepts image values ā not just colors.
Use it with images and gradients to adapt visuals based on color scheme.
background: light-dark(url(light.png), url(dark.png));
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developer.mozilla.org/en-US/docs/...
š¦ Firefox 150 ships ariaNotify() on Document and Element.
Queue text to be announced by a screen reader ā a more ergonomic and reliable alternative to ARIA live regions.
Read Now š
developer.mozilla.org/en-US/docs/...
š¦ Firefox 150: web extensions can now use the Web Authentication API.
Extensions can create and retrieve WebAuthn credentials for any domain covered by their host permissions.
Read Now š
developer.mozilla.org/en-US/docs/...
This article provides information about the changes in Firefox 152 that affect developers. Firefox 152 is the current Beta version of Firefox and ships on June 16, 2026.
