--- title: Firefox 155 Available With Faster Page Loads Via Happy... description: Firefox 155 introduces Happy Eyeballs v3, which now tries multiple connection paths concurrently including HTTP/2 and HTTP/3 alongside IPv4/IPv6, using modern... canonical: https://daily.dev/posts/firefox-155-available-with-faster-page-loads-via-happy-eyeballs-v3-quic-v2-for-http-3-tmppatnix twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Firefox 155 Available With Faster Page Loads Via Happy Eyeballs v3, QUIC v2 For HTTP/3 | daily.dev og:description: Firefox 155 introduces Happy Eyeballs v3, which now tries multiple connection paths concurrently including HTTP/2 and HTTP/3 alongside IPv4/IPv6, using modern... og:url: https://daily.dev/posts/firefox-155-available-with-faster-page-loads-via-happy-eyeballs-v3-quic-v2-for-http-3-tmppatnix og:image: https://api.daily.dev/og/posts/TmPPatNix.png og:image:alt: Firefox 155 Available With Faster Page Loads Via Happy Eyeballs v3, QUIC v2 For HTTP/3 og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Firefox 155 Available With Faster Page Loads Via Happy Eyeballs v3, QUIC v2 For HTTP/3 **[Phoronix](https://daily.dev/sources/phoronix)** · 2 min read · 1 upvotes · 0 comments ## Summary Firefox 155 introduces Happy Eyeballs v3, which now tries multiple connection paths concurrently including HTTP/2 and HTTP/3 alongside IPv4/IPv6, using modern DNS records to pick the fastest option. It also adds QUIC v2 support for HTTP/3 connections when servers support it. The release includes Smart Window, an AI-powered browsing window (initially limited to USA, Canada, France), a fix for a Linux sleep bug, plus developer-facing changes like WebAssembly Compact Import Section, WebAssembly Wide Arithmetic, the font-width CSS property, improved WebRTC interoperability, and the progress() CSS function. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What does Happy Eyeballs v3 do in Firefox 155? Happy Eyeballs v3 makes Firefox 155 attempt multiple ways of connecting to a website at once and use whichever succeeds first, speeding up page loads. It builds on the earlier IPv4 vs IPv6 parallel selection by also using modern DNS records to discover supported protocols and concurrently trying HTTP/2 and HTTP/3 connections. _Developers tracking browser network stack changes can follow HTTP/3 and Happy Eyeballs updates on daily.dev._ ### Does Firefox 155 support QUIC version 2? Yes, Firefox 155 adds support for QUIC version 2 for HTTP/3 connections, using it whenever the server selects it through compatible version negotiation. This follows the addition of Happy Eyeballs v3, which also improves how Firefox picks the fastest connection path for a page load. _Anyone comparing HTTP/3 and QUIC support across browsers can keep up with releases like this on daily.dev._ ### What new CSS and WebAssembly features are in Firefox 155? Firefox 155 adds developer-facing changes including WebAssembly Compact Import Section support, WebAssembly Wide Arithmetic for 128-bit arithmetic instructions, the font-width property as the standard name for font-stretch, improved WebRTC interoperability, and support for the progress() CSS function. _Web developers adopting new CSS and WebAssembly capabilities can track browser feature rollouts on daily.dev._ --- Tags: [#webassembly](https://daily.dev/tags/webassembly), [#firefox](https://daily.dev/tags/firefox) [View this post on daily.dev](https://daily.dev/posts/firefox-155-available-with-faster-page-loads-via-happy-eyeballs-v3-quic-v2-for-http-3-tmppatnix) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Firefox 155 Available With Faster Page Loads Via Happy Eyeballs v3, QUIC v2 For HTTP/3","url":"https://daily.dev/posts/firefox-155-available-with-faster-page-loads-via-happy-eyeballs-v3-quic-v2-for-http-3-tmppatnix","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/firefox-155-available-with-faster-page-loads-via-happy-eyeballs-v3-quic-v2-for-http-3-tmppatnix"},"datePublished":"2026-08-31T21:00:34.643Z","dateModified":"2026-09-01T14:06:22.357Z","description":"Firefox 155 introduces Happy Eyeballs v3, which now tries multiple connection paths concurrently including HTTP/2 and HTTP/3 alongside IPv4/IPv6, using modern...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/383ccb21e9615740773633ac5f43e6e7?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/383ccb21e9615740773633ac5f43e6e7?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Phoronix","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Phoronix","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/6a26ba379dd64932830aa0c9803dd7ee","url":"https://daily.dev/sources/phoronix"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/firefox-155-available-with-faster-page-loads-via-happy-eyeballs-v3-quic-v2-for-http-3-tmppatnix","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":1},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"webassembly,firefox","timeRequired":"PT2M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Phoronix","item":"https://daily.dev/sources/phoronix"},{"@type":"ListItem","position":3,"name":"Firefox 155 Available With Faster Page Loads Via Happy Eyeballs v3, QUIC v2 For HTTP/3"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/firefox-155-available-with-faster-page-loads-via-happy-eyeballs-v3-quic-v2-for-http-3-tmppatnix#faq","mainEntity":[{"@type":"Question","name":"What does Happy Eyeballs v3 do in Firefox 155?","acceptedAnswer":{"@type":"Answer","text":"Happy Eyeballs v3 makes Firefox 155 attempt multiple ways of connecting to a website at once and use whichever succeeds first, speeding up page loads. 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