The responseEnd read-only property returns a timestamp immediately after the browser receives the last byte of the resource or immediately before the transport connection is closed, whichever comes first.

Unlike many other PerformanceResourceTiming properties, the responseEnd property is available for cross-origin requests without the need of the Timing-Allow-Origin HTTP response header.

A DOMHighResTimeStamp immediately after the browser receives the last byte of the resource or immediately before the transport connection is closed, whichever comes first.

The responseEnd and fetchStart properties can be used to measure the overall time it took to fetch the final resource (without redirects). If you want to include redirects, the overall time to fetch is provided in the duration property.

const timeToFetch = entry.responseEnd - entry.fetchStart;

Example using a PerformanceObserver, which notifies of new resource performance entries as they are recorded in the browser's performance timeline. Use the buffered option to access entries from before the observer creation.

const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    const timeToFetch = entry.responseEnd - entry.fetchStart;
    if (timeToFetch > 0) {
      console.log(`${entry.name}: Time to fetch: ${timeToFetch}ms`);
    }
  });
});

observer.observe({ type: "resource", buffered: true });

Example using Performance.getEntriesByType(), which only shows resource performance entries present in the browser's performance timeline at the time you call this method:

const resources = performance.getEntriesByType("resource");
resources.forEach((entry) => {
  const timeToFetch = entry.responseEnd - entry.fetchStart;
  if (timeToFetch > 0) {
    console.log(`${entry.name}: Time to fetch: ${timeToFetch}ms`);
  }
});