swrDelta

You can specify a custom stale-while-revalidate period for CDNs to consume in the Cache-Control header for ISR enabled pages.

Open next.config.js and add the swrDelta config:

module.exports = {
  // one year in seconds
  swrDelta: 31536000,
}

Now instead of an empty stale-while-revalidate period being provided in the Cache-Control header, the custom period will be included.