Published: November 10, 2026
In this new era of agentic web development, developers expect their coding agents to be experts at building for the web. And while the latest frontier coding models are quite capable and can usually produce something that works, if you ask a web development expert to review the AI-generated code, they can almost always find ways to make the code faster, more accessible, or more secure.
Chrome is investing heavily in the future of agentic web development, and to address this challenge, we introduced an early preview of Modern Web Guidance at Google I/O in May. Modern Web Guidance is a set of skills that embed web platform expertise, best practices, and browser compatibility data directly into your coding agents.
Today we're excited to announce the stable release of Modern Web Guidance version 1.0, which includes:
- New modernization workflow that scans your existing codebase to help your agent find opportunities to safely modernize.
- Expanded guide database targeting hundreds of verified AI knowledge gaps with expert-vetted, cross-browser solutions.
- Deeper human expert review for every guide, including sign-off from content area tech leads and a dedicated accessibility review on our user-facing guides.
- Full evaluation coverage across all of our guides with a public eval dashboard showing the measurable improvements compared to agents without Modern Web Guidance.
With version 1.0, we're also excited to share that Modern Web Guidance is becoming a cross-browser effort, with Firefox and Edge joining Chrome to support, improve cross-browser compatibility, and contribute to the project. Building on our shared work with Baseline, our goal is to ensure that anyone coding with an agent can take full advantage of the power and capabilities of the modern web platform.
Regardless of what models or agent harnesses you're using, if you're building for the web, Modern Web Guidance belongs in your agentic workflow.
To install Modern Web Guidance, run this command from your project directory:
npx modern-web-guidance@latest install
Or if you already installed an earlier version, you can update to 1.0 by running:
npx modern-web-guidance@latest update
For additional installation instructions or to learn more, check out the Modern Web Guidance documentation, or watch this video for a brief overview:
Why developers and businesses should use Modern Web Guidance
It's undeniable that coding agents have helped developers write code faster than ever before. But in a world where everyone is using coding agents, speed is no longer a competitive advantage.
These days, it's more important than ever to differentiate on fundamental factors like usability and quality of experience. Here are a few ways Modern Web Guidance can help:
Reinforce best practices that models often miss
While frontier coding models do have a good grasp on many best practices, our evals show that there are still a number of important areas where they fall short, such as:
- Accessibility: Keyboard focus and inert management, reduced-motion support, and accessible form validation.
- User experience: Swipe and touch gestures, dialog and popover transitions, and light/dark theme implementations.
- Performance: Main-thread task scheduling, offscreen rendering isolation, and layout shift prevention.
- Security: Safe HTML sanitization, strict Content Security Policies, and passkey credential management.
Accessibility best practices are particularly important to get right because mistakes like bad ARIA can make a page less accessible than no ARIA at all. For version 1.0, our user-facing guides were reviewed and tested with real assistive technologies by accessibility experts who rely on them every day.
Use the best web feature for the job
AI models are very good at figuring out how to make something work with JavaScript, but in many cases, there are HTML or CSS features that can do the same thing with much less code. And since they're handled by the browser, they usually perform better and come with accessibility affordances. For example:
- Features to animate popovers and dialogs
- Features to enhance scroll- and swipe-based interactions
- Better APIs for smooth and fluid page transitions
New features can also improve the experience of a site in ways that matter to users. For example:
- Passkeys and WebAuthn: For faster and more secure login experiences
- Autofill: To improve checkout flows (especially on mobile) that often fail when using custom JavaScript-based form controls
Modern Web Guidance is designed to recommend the best feature for the job, based on your browser support requirements. Its guides have embedded Baseline and browser compatibility data, so it can tailor its recommendations to your project's needs.
Scan your codebase and find opportunities to modernize
Most web development doesn't happen in brand-new projects. It happens in existing codebases that have accumulated years of outdated workarounds, unnecessary dependencies, and polyfills that are no longer needed.
Version 1.0 adds a new modernization workflow that can analyze your existing HTML, CSS, JavaScript, and package.json to find opportunities to safely upgrade, and then guide your agent through the changes.
/modern-web-guidance Modernize the code in this directory
In this first release, the modernization workflow uses static analysis to check for a limited set of patterns. We chose to start with a narrow scope that yields predictable results, and then expand from there. Over time, we plan to cover many more areas, including agentic audits where your agent reasons about your code directly instead of just matching known patterns.
Stay up to date as the web platform evolves
The web platform is a moving target. New features ship in browsers every milestone, and existing features that you perhaps couldn't use before are becoming Baseline with each new browser release.
Since Modern Web Guidance is built on top of Baseline compatibility data, and its recommendations are maintained by browser engineers, web standards experts, and accessibility specialists, these recommendations evolve along with the platform itself, and now your project can too.
Learn about new web features and best practices
While Modern Web Guidance is primarily built as a tool for agents, one thing we've heard from many developers is that they've actually found the guidance to be quite useful on its own—as a learning resource.
Even in this era of agentic coding, there's still value in building up domain expertise. And Modern Web Guidance can help you do that: either by reading the guides themselves, or using the CLI to search use cases and discover new techniques that may be relevant to your project.
Pair Modern Web Guidance with Chrome DevTools for agents
In agentic web development, authoring code is only one part of the workflow. You also need to run that code to ensure it works as expected. This is why we recommend developers use Modern Web Guidance along with Chrome DevTools for agents.
- Modern Web Guidance gives your agent the up-front expertise needed to write code following modern best practices.
- Chrome DevTools for agents gives your agent runtime visibility so it can verify, debug, and optimize that code across a wide range of device capabilities, user preferences, and network conditions.
Together these help your agent arrive at a better solution in fewer turns. Next are a few examples of how you can use these tools together to maximize effectiveness:
Optimize until you hit your performance target
Modern Web Guidance can teach your agent how to effectively break up long-running JavaScript tasks that block the main thread, but it can't test your code to see how long those JavaScript tasks actually block the main thread for.
With Chrome DevTools for agents, you can run a performance trace on a simulated low-end CPU to see whether or not you have a problem, and then use the performance advice from Modern Web Guidance to iterate until your code never blocks the main thread for more than 50 milliseconds (so it doesn't contribute to poor INP).
Test and refine your animations
Modern Web Guidance can show your agent how to properly and performantly animate features like modal dialogs, tooltips, and popover menus, but even with this guidance you still need to verify that the animations actually work and look good when used in the context of your full application.
Chrome DevTools for agents can run your code, interact with the page, and take a screen recording of the animation in action. It can then study the recording to ensure both that the animation runs and that it fits the style and feel of the rest of the site.
You can also use Chrome DevTools for agents to verify that when prefers-reduced-motion is set, the component honors the user's preferences.
Cache views without memory leaks
Modern Web Guidance can teach your agent how to make SPA transitions feel instant by rendering and caching views in memory, while also properly hiding them from the accessibility tree.
However, when doing this it's important to ensure you properly clean up unused views to not leak memory if the user stays on the page for a long time. Chrome DevTools for agents has memory debugging tools, so your agent can ensure memory use isn't increasing without bound.
For a closer look at how to use Modern Web Guidance and Chrome DevTools for agents together, check out this video:
Success stories
Engineering teams around the world are already using Modern Web Guidance and Chrome DevTools for agents to improve code quality, speed up delivery, and eliminate manual debugging bottlenecks:
Pensionbazaar and Policybazaar
Pensionbazaar, a new retirement planning platform launched by Indian fintech company Paisabazaar, paired Modern Web Guidance with Chrome DevTools for agents to build and verify new pages, shortening turnaround by more than 90% (from about four days to a few hours) and reducing UI bugs on new screens by over 90%. Its sister platform Policybazaar, one of India's leading insurance platforms with more than 97 million registered customers, used Chrome DevTools for agents to automate performance audits across about 30 high-traffic landing pages, cutting manual auditing effort by 92%:
"For Pensionbazaar, our priority was building quality code from day one to avoid technical debt later. Modern Web Guidance steered our coding agent to adopt modern web standards and performance best practices while respecting our specific browser compatibility targets. This made our frontend code reviews substantially easier and faster, ultimately improving our development turnaround time."
—Aman Soni, Engineering Manager, Policybazaar
WeTV
WeTV, Tencent's international video streaming platform, added an AI coding agent to its CI/CD pipeline that uses Chrome DevTools for agents to diagnose performance regressions and Modern Web Guidance to fix them using modern web platform features. The agent now automatically diagnoses and resolves 90% of failed performance checks, cutting debugging and resolution time by 87% (from four hours to 30 minutes, including manual evaluation):
"The results have been very effective in terms of both speed and quality. The diagnostic insights provided by Chrome DevTools for agents and Modern Web Guidance gave us reliable references for fixing complex layout issues. We perform strict verification after every fix, and the current success rate and stability have significantly improved our release confidence."
—Yangjie Zheng, Head of Engineering, WeTV (Tencent)
note inc.
note inc., one of Japan's largest creator and media platforms with over 90 million monthly active users, used Modern Web Guidance alongside its in-house design system as part of an ongoing effort to modernize its Next.js frontend. Across a 180-run evaluation on its production codebase, Modern Web Guidance raised pass rates on modern web checks from 61% to 94% by steering agents to use native HTML and CSS features instead of custom JavaScript for scroll animations, tooltips, and accordions. It also increased proper LCP image prioritization by 28% across 431 merged PRs:
"Our mission at note is 'Start, and Keep on Creating,' so our platform has to stay fast and accessible for every creator and reader. As more of our code is written with AI coding agents, Modern Web Guidance helps them reach for modern, standards-based solutions instead of falling back on older JavaScript patterns. It also points out details that are easy to miss, such as image loading priority and form accessibility. Combined with our design system, it lets us keep improving note while keeping our UI consistent."
—Takehiko Itabashi, VP of Technology, note inc.
MetaMask
MetaMask, a self-custodial financial platform with more than 100 million downloads across approximately 190 countries, runs Modern Web Guidance as an automated review bot on every pull request to its open source browser extension, configured with just a three-line prompt. In its first five weeks, the bot reviewed roughly 480 pull requests and commented on 64 of them, leading engineers to fix 43 findings (mostly accessibility, HTML semantics, and forms issues that linters don't catch) with a median time of 15 minutes from comment to fix:
"The reviews are really helpful. They've helped surface and get our engineers familiar with modern APIs like Interest invokers and the Popover API. It hasn't increased PR review times, if anything it likely reduced them. The issues MWG caught would have otherwise required a human reviewer familiar with these modern web techniques."
—Francis Nepomuceno, UX Engineer, MetaMask
Ecosystem and community support
Modern Web Guidance started as an initiative within Chrome, but reaching this 1.0 milestone was a collaborative effort with numerous experts across the web community.
Thank you to the content area tech leads overseeing each web platform area, our browser partners at Firefox and Edge, the independent web standards and accessibility experts who authored and tested guides, and all of the open source contributors on GitHub who helped shape this release!
If you spot a gap in what coding agents know about the web, or want to help improve an existing guide, see the contribution guide to get involved.
Get started with Modern Web Guidance
To add Modern Web Guidance to your project, run the CLI installer from your project directory:
npx modern-web-guidance@latest install
Or if you already installed an earlier version, you can update to 1.0 by running:
npx modern-web-guidance@latest update
In addition to the CLI, you can install and update Modern Web Guidance directly through most popular coding agent plugin marketplaces, including Claude Code, Codex, Cursor, Antigravity, Copilot, WebStorm, Kimi Code, and Grok Build.
To learn more, check out these resources: