![Addy Osmani](https://web.dev/images/authors/addyosmani.jpg) Addy Osmani [X](https://twitter.com/addyosmani) [GitHub](https://github.com/addyosmani) [Bluesky](https://bsky.app/profile/addyosmani.bsky.social)
On the Chrome team, we are exploring a new **[back/forward cache](https://www.chromestatus.com/feature/5815270035685376)** to cache pages in-memory (preserving JavaScript \& DOM state) when the user navigates away. This is definitely not a trivial endeavor but if it succeeds it will make **navigating back and forth** *very* fast. A back/forward cache (bfcache) caches whole pages (including the JavaScript heap) when navigating away from a page, so that the full state of the page can be restored when the user navigates back. Think of it as **pausing** a page when you leave it and **playing** it when you return. Here is a first-look of an **early prototype** of back/forward cache in action on desktop: [Video](https://www.youtube.com/watch?v=eusKoHPAWtU) We also have a preview of the back/forward cache working on Chrome for Android: [Video](https://www.youtube.com/watch?v=cuPsdRckkF0) We estimate this change could **improve the performance of up to 19% of all navigations** for mobile Chrome. You can find more detail about this feature in the [bfcache explainer](https://docs.google.com/document/d/1mrgp7XzR16rd1xqFYOJgC1IP0NPLZFaRU5Ukj3-TlLw/edit#heading=h.d9wqdzopmdcf). There is medium cross-browser interop risk with this change. Both [Firefox](https://developer.mozilla.org/docs/Mozilla/Firefox/Releases/1.5/Using_Firefox_1.5_caching) and [Safari](https://webkit.org/blog/427/webkit-page-cache-i-the-basics/) already have back-forward cache implementations that are subtly different. Chrome is opting not to use WebKit's implementation of bfcache due to incompatibility with Chrome's multi-process architecture. Our formal intent-to-implement for the back-forward cache is on [blink-dev](https://groups.google.com/a/chromium.org/forum/#!msg/blink-dev/OVROmzNUng0/1gTmi-I3EQAJ) for anyone wishing to contribute to the discussions. *Thanks to Arthur Sonzogni, Alexander Timin, Kenji Baheux, and Sami for their help putting together our prototype videos.*