The gatsby-browser.js API file

The file gatsby-browser.js lets you respond to actions within the browser, and wrap your site in additional components. The Gatsby Browser API gives you many options for interacting with the client-side of Gatsby.

The APIs wrapPageElement and wrapRootElement exist in both the browser and Server-Side Rendering (SSR) APIs. If you use one of them, consider if you should implement it in both gatsby-ssr.js and gatsby-browser.js so that pages generated through SSR with Node.js are the same after being hydrated with browser JavaScript.

To use Browser APIs, create a file in the root of your site at gatsby-browser.js. Export each API you want to use from this file.