A number of important announcements were made during Google I/O 2021 event held by Google. The conference covered key Google's products including Android, Wear OS, Google Health, Project Starline and web. I propose you have a look at the main updates on the web that would be especially useful for developers and SEO specialists.

New privacy technologies

Sandbox approach is taken with user data and tracking, resulting in a web where your identity and activity are private by default.

In 2019 was announced about changing the behaviour of cookies in Chrome. Moving them from being visible across websites by default to be required to opt in to use third-party cookies across sites. This privacy-preserving default behavior is now enforced in Chrome, Edge, and, very soon, Firefox.

Google I/O 2021: Browser adoption of "SameSite" cookie policy

Today on third-party cookies rely: federated login, personalised ads and conversion tracking. So, traditionally, in order, for example, to measure the effectiveness of an advertising campaign, users were tracked with a third-party cookie. 

Now, thanks to Attribution Reporting API it is possible to share data between sites without identifying the user. The browser keeps track of the ad conversion and sends an encrypted report to the advertiser about conversion events.

Attribution Reporting is one of many new API proposals in the Privacy Sandbox project.

Google I/O 2021

Attribution Reporting API is also a move towards the direction of the future without third-party cookies.

Google I/O 2021 

New capabilities of the web:

• New app shortcuts feature. Operating systems that support this feature are Android, Chrome OS, Windows, and macOS. With the Badging API, web apps can give the user a prompt that there’s an opportunity to re-engage by decorating the app’s icon.

Google I/O 2021: New app shortcuts feature

• Declarative Link Capturing - new API that enables installed web apps to launch automatically when the user clicks on an appropriate link.

Google I/O 2021: Declarative Link Capturing

• Improved Chrome’s web app installation UI: 

*on the desktop, there is an omnibox icon and in-product help to explain this feature to users. 

*on Android, the dialogue started to look richer and more familiar to users. 

Besides, developers now can customize images and texts that are specified in the web app’s manifest file.

Google I/O 2021: Improved Chrome’s web app installation UI on Android

• Multi-Screen Window Placement API. It allows web apps to discover all of the connected displays and control where the window is placed on those screens.

Google I/O 2021: Multi-Screen Window Placement API

• Web apps can read and write to the user's local file system using the File System Access API, enabling a seamless user experience, persisting state to disk and working with existing files.

• New File Handling API. It will allow web applications to be registered as file type handlers, enabling users to open files directly in a web app from OS file browsers.

• API for Web HID will allow the web to communicate with similar devices to game controllers, digital pianos, headsets, etc. For example, Nintendo’s Joy-Con controller is a device that supports Web HID protocol.

• Gamepad API is now supported by the web as well.

• Web Serial API created to support serial ports.

• WebGPU - the new next-generation graphics API, designed to unlock a whole new level of graphics performance on the web.

• Intensive timer throttling a new feature available for some Chrome users that detects when a browser tab has been in the background for more than five minutes and as long as the tab isn’t playing any audio or video, Chrome slows down how frequently it executes timer-based JavaScript code on that tab. 

• A similar concept is also applied with CSS by shipping support for a new CSS property called content-visibility. When this property is set to auto on an element, you’re giving the browser permission to skip rendering the contents of that element tree if it isn’t currently visible on the user’s display, and this can lead to a dramatic speed increase for content-heavy sites.

• Chrome’s BFCache (it keeps some web pages loaded in memory after you’ve navigated away from them, for example, if a user clicks back or forward, the page is displayed instantly) will be available on desktop soon. 

• New approaches to pre-rendering that are private and safe. One of these involves a new pre-rendering API that would enable developers to experiment with this on-site pre-loading later this year.

• Development of scrolls to images API. Scroll to text was added to Chrome 80 in February of last year. By adding a new type of expression to the end of the URL, browsers can position the viewport to a specific text element and highlight it in some way. Besides images, Google continues to explore other element types.

• New document transition APIs and support for a number of graphical transitions between elements to enable the user to perceive a seamless experience.

• Cross-device one-time passwords for the web. This feature enables you to receive a one-time password to login to the site on your Android phone, and then have it automatically transferred to a Chrome browser running on some other device like a laptop.

Google I/O 2021: Cross-device one-time passwords for the web

More tools for developers

Web Assembly is a performance technology, which provides a standard for compiling code to a fast and efficient format that can be executed in the browser by modern JavaScript engines like V8.

Web Assembly received a major performance boost because of the implementation of the support for SIMD processor instructions in V8, which enables certain classes of apps to run much faster. Google Meet provides a powerful example of SIMD in action. It is planned to ship SIMD to all Chrome users in the coming months.

Web Assembly is also frequently used to bring non-JavaScript codebases to the web.

Chrome for Android gained Web Assembly threads as of Chrome 88 in January of this year.

It was also enhanced V8′s Web Assembly debugging experience with support for breakpoints and variable inspection available in Chrome DevTools.

Google I/O 2021: Chrome DevTools

In addition to interpreting JavaScript, V8 also compiles code on the fly for more efficient execution. Sparkplug - is a whole new compiler.

Google I/O 2021: Sparkplug

Web.dev is the site that includes detailed tutorials on key topics, the latest news, and provides access to the Lighthouse website auditing tool.

With Lighthouse, you get a comprehensive report on how to improve your website, across a variety of categories such as performance, accessibility, and SEO.

Google I/O 2021: Lighthouse

Core Web Vitals are three performance metrics available in Lighthouse that are impactful on the user experience.

Google I/O 2021: Core Web Vitals

For example, the Italian publisher GEDI implemented a branded placeholder in order to reserve space for ads in their ad slots on the page, which improved their layout stability, and then by deferring the loading of some of their JavaScript code until after the page was visible, they improved the perceived page loading speed. As a result, 8% improvement in the bounce rate on their mobile article pages.

Google I/O 2021: Core Web Vitals - case studies

Google Search has also announced that Core Web Vitals will soon be a part of how pages are ranked in search results.

Google I/O 2021: Core Web Vitals for SEO