Your Wix widget loads from whichever deployment rendered the page, and that render can be cached for 35 hours

A recently discovered behavior of Wix apps built with the Wix CLI reveals that the deployment from which a widget loads can change after the page is rendered. This cache can hold the rendered HTML for up to 35 hours, with the oldest observed cache being 125,021 seconds old, or about 34.7 hours. This means that merchants do not need to republish their sites to receive widget updates, as the rendered page is served from a cache.

When Wix builds an app using the CLI, it creates a new deployment for each release. The dashboard page immediately picks up the new deployment, but the custom element merchants drop onto their pages may not. Up until this discovery, it was believed that merchants had to republish their sites to receive widget fixes. However, this is not the case, as the real mechanism allows for more efficient updates.

To demonstrate this, researchers observed the widget loading from either the old or new deployment after a release. They found that old deployments stayed online, and the new deployment was referenced within minutes of the release. In one case, two sites served two different old bundles before switching to the new one within minutes. The researchers emphasize the importance of rechecking the cached page a few hours after a change and examining the headers to understand the proper update mechanism.

To reproduce this behavior, one can use a published site with the widget installed and the slug part of the app host. The steps include fetching the cached render, looking at the age and prefix, and forcing a fresh render by changing the URL with a random query string. If the cached render shows an old prefix and a large age, while the fresh render shows the current prefix, this confirms the mechanism at work.

The Wix dashboard now informs merchants that their cached pages may still load the older version but refreshes them on their own over time. The dashboard compares the prefixes of published home pages with the prefix of the dashboard itself to determine if the site is running the latest deployment. This approach avoids republishing unnecessarily and ensures merchants are informed about widget updates.