This article describes the methods and URLs used by the Speedtest feature in the Mist portal to measure download and upload speeds.

The Mist Speedtest feature uses Cloudflare's speed test infrastructure to perform bandwidth measurements. Mist is partnered with Cloudflare to conduct these speed tests.

The speed test first establishes the required connections/sockets with Cloudflare and then performs separate download and upload tests.

More information about Cloudflare's speed test infrastructure is available at:
Cloudflare Speed Test

URLs Used for Download Testing

The following Cloudflare endpoints are used to test download performance:

• https://h3.speed.cloudflare.com/__down?bytes=10
• https://h3.speed.cloudflare.com/__down?bytes=10000000000

URL Used for Upload Testing

The following Cloudflare endpoint is used to test upload performance:

• https://h3.speed.cloudflare.com/__up

Troubleshooting / Additional Information

Detailed information about the execution of the Speedtest, including the connections and requests made during the test, can be found in the following SSR log file:

/journal/128t-testing-tools-controller.log

Reviewing this log can help identify connectivity or Speedtest-related issues and verify the Cloudflare endpoints being accessed during the test.