WebNN, Built-in AI, WebMCP: What’s New in Web AI?

Generative AI is becoming a key part of modern software architecture, and its presence in web apps is growing. As demand increases, vendors and specification authors are working to make AI capabilities more accessible and integrated into the web platform.

In this session, Christian Liebel—member of the W3C TAG and WebML Working Group—will share what's cooking behind the scenes in Web AI. You'll get an update on the latest advancements in the WebNN API, Chromium's Built-in AI APIs, WebMCP, emerging developer tools, usage statistics, and the real-world challenges that browser vendors and standards authors are navigating to bring AI to the web.

Transcript

1. WebNN, Built-in AI, WebMCP What’s New in Web AI? Christian Liebel @christianliebel Consultant
2. WebNN, Built-in AI, WebMCP What’s New in Web AI? Christian Liebel Hello, it’s me. Angular, PWA & Generative AI Microsoft MVP & Google GDE W3C WebApps, WebML & TAG christian.liebel @thinktecture.com
3. WebNN, Built-in AI, WebMCP What’s New in Web AI? Why should you care about AI? Rule-based algorithms are limited in their capabilities.
4. WebNN, Built-in AI, WebMCP What’s New in Web AI? Why should you care about AI? Use AI to implement use cases that are difficult or impossible to implement using rule-based algorithms.
5. WebNN, Built-in AI, WebMCP What’s New in Web AI? Generative AI Cloud Providers Examples
6. WebNN, Built-in AI, WebMCP What’s New in Web AI? Generative AI Cloud Providers Drawbacks Require a (stable) internet connection Subject to network latency and server availability Data is transferred to the cloud service Require a subscription
7. WebNN, Built-in AI, WebMCP What’s New in Web AI? Web AI Landscape Bring Your Own AI (BYOAI) Built-in AI (BIAI) • Frameworks • Transformers.js • APIs • WebGPU • WebNN • Cross-Origin Storage • Writing Assistance APIs • Summarizer API • Writer API • Rewriter API • Proofreader API • Translator & Language Detector APIs • Prompt API • Embedding API NEW! Agentic Browsing & WebMCP
8. WebNN, Built-in AI, WebMCP What’s New in Web AI? Web AI Landscape Bring Your Own AI (BYOAI) Built-in AI (BIAI) • Frameworks • Transformers.js • APIs • WebGPU • WebNN • Cross-Origin Storage • Writing Assistance APIs • Summarizer API • Writer API • Rewriter API • Proofreader API • Translator & Language Detector APIs • Prompt API • Embedding API NEW! Agentic Browsing & WebMCP
9. WebNN, Built-in AI, WebMCP What’s New in Web AI? Transformers.js https://huggingface.co/docs/transformers.js/index DEMO
10. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebGPU – Grants low-level access to the Graphics Processing Unit (GPU) – Near native performance for machine learning applications – Supported by Chromium-based browsers on Windows and macOS from version 113, Safari 26, and Firefox 141 on Windows/Firefox 145 on macOS 26 Tahoe on Apple Silicon
11. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebNN – Grants web apps access to the device’s CPU, GPU and Neural Processing Unit (NPU) – In specification by the WebML Working Group at W3C – Implementation in progress in Chromium (behind a flag) – Positive standard positions by Chromium and Firefox Source: https://webmachinelearning.github.io/webnn-intro/
12. WebNN, Built-in AI, WebMCP What’s New in Web AI? Transformers.js WebNN https://webnn.io/en/learn/tutorials/transformers-js/transformers-js
13. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebNN DEMO https://huggingface.co/webnn/spaces
14. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebNN: near-native inference performance Source: Intel. Browser: Chrome Canary 118.0.5943.0, DUT: Dell/Linux/i7-1260P, single p-core, Workloads: MediaPipe solution models (FP32, batch=1)
15. WebNN, Built-in AI, WebMCP What’s New in Web AI? Bring Your Own AI Drawbacks Models can’t be shared across origins Inference is fast, but doesn’t reach full native speed
16. WebNN, Built-in AI, WebMCP What’s New in Web AI? Cross-Origin Storage https://github.com/wicg/cross-origin-storage DEMO
17. WebNN, Built-in AI, WebMCP What’s New in Web AI? Web AI Landscape Bring Your Own AI (BYOAI) Built-in AI (BIAI) • Frameworks • Transformers.js • APIs • WebGPU • WebNN • Cross-Origin Storage • Writing Assistance APIs • Summarizer API • Writer API • Rewriter API • Proofreader API • Translator & Language Detector APIs • Prompt API • Embedding API NEW! Agentic Browsing & WebMCP
18. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI Website HTML/JS Browser Operating System Apple Intelligence Gemini Nano Internet
19. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI – Initiative by Google Chrome – Exploratory APIs for local experiments and use case determination – Downloads AI models into Google Chrome – Models are shared across origins – Uses native APIs directly (full performance) https://developer.chrome.com/docs/ai/built-in
20. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI APIs about://flags {Writer, Rewriter, Proofreader, Semantic Embedder} API à Enabled
21. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI APIs Incubated by the WebML CG DEMO https://webmachinelearning.github.io/incubations/
22. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI Prompt API const languageModel = await LanguageModel.create(); console.log(await languageModel.prompt("Capital of Norway?"));
23. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI Prompt API Polyfill Supports two backends: – Cloud backend: needs an API key (no longer local/offline-capable) – Local backend: uses Transformers.js (via WebGPU or Wasm) npm install prompt-api-polyfill https://developer.chrome.com/docs/ai/prompt-api-polyfill
24. WebNN, Built-in AI, WebMCP What’s New in Web AI? Multimodal Models
25. WebNN, Built-in AI, WebMCP What’s New in Web AI? Multimodal Models DEMO
26. WebNN, Built-in AI, WebMCP What’s New in Web AI? Structured Output DEMO https://bandarra.me/apps/flyby/
27. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI APIs TypeScript Definitions
28. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI APIs const semanticEmbedder = await SemanticEmbedder.create(); const result1 = await semanticEmbedder.embed("The store is closed."); const result2 = await semanticEmbedder.embed("The shop is not open."); const similarity = cosineSimilarity(result1, result2); https://github.com/explainers-by-googlers/embedding-api
29. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI APIs TrAIlblazers Blog https://developer.chrome.com/blog/build-new-features-using-built-in-ai-in-chrome-io2026
30. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI APIs https://developer.chrome.com/blog/build-new-features-using-built-in-ai-in-chrome-io2026
31. WebNN, Built-in AI, WebMCP What’s New in Web AI? Built-in AI Prompt API Standard Positions https://github.com/WebKit/standards-positions/issues/495 https://github.com/mozilla/standards-positions/issues/1213
32. WebNN, Built-in AI, WebMCP What’s New in Web AI? Web AI Landscape Bring Your Own AI (BYOAI) Built-in AI (BIAI) • Frameworks • Transformers.js • APIs • WebGPU • WebNN • Cross-Origin Storage • Writing Assistance APIs • Summarizer API • Writer API • Rewriter API • Proofreader API • Translator & Language Detector APIs • Prompt API • Embedding API NEW! Agentic Browsing & WebMCP
33. WebNN, Built-in AI, WebMCP What’s New in Web AI? Agentic Browsers
34. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebMCP – Allows websites to register tools for use by browser or external AI agents – Joint effort by Microsoft and Google – In specification by the WebML CG – In Origin Trial since Chromium 149, expected Shipping in Chromium 157 (https://chromestatus.com/feature/5117755 740913664) https://github.com/webmachinelearning/webmcp
35. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebMCP https://webmachinelearning.github.io/webmcp/
36. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebMCP API Imperative Declarative document.modelContext.registerTool({ "name": "start_game", "description": "Start a new game.", "inputSchema": {}, "execute": () => { // Do something }, }); <form id="reservationForm" toolname="book_table_le_petit_bistro" tooldescription=...> <input name="name" toolparamdescription="Customer's full name (min 2 chars)" /> </form>
37. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebMCP Dev Tools Support (Chromium 149+)
38. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebMCP Maze Imperative DEMO https://googlechromelabs.github.io/webmcp-tools/demos/pizza-maker/
39. WebNN, Built-in AI, WebMCP What’s New in Web AI? WebMCP Maze Agent-only! DEMO https://googlechromelabs.github.io/webmcp-tools/demos/webmcp-maze/
40. WebNN, Built-in AI, WebMCP What’s New in Web AI? Web AI Pros & Cons + Data does not leave the browser (privacy) + High availability (offline support) + Low latency + Stability (no external API changes) + Low cost – Lower response quality – Less capable – High system (RAM, GPU) and bandwidth requirements – Large model size, models cannot always be shared – Model initialization and inference are relatively slow – APIs are experimental
41. WebNN, Built-in AI, WebMCP What’s New in Web AI? Web AI https://www.apple.com/newsroom/2026/08/apple-introduces-m6-and-m5-ultra-for-a-big-leap-in-performance-and-ai-compute/
42. Thank you for your kind attention! Christian Liebel @christianliebel christian.liebel@thinktecture.com