Reliable Data Sending with JavaScript's Beacon API: Ditching Unreliable `beforeunload`
2025-09-04
Sending data reliably to servers when a user leaves a website has always been a challenge. Traditional methods using the `beforeunload` event with `fetch` or `XMLHttpRequest` are unreliable, as browsers may cancel requests for a better user experience. JavaScript's Beacon API offers a 'fire-and-forget' solution; the browser doesn't wait for a response, ensuring data is sent reliably. While the Beacon API limits data size and only supports POST requests, it's perfect for sending small, critical data like analytics or page leave events. It's also great for any scenario requiring reliable asynchronous data sending, such as real-time data synchronization.
Development
data sending