Description

The HTTP response status code 527 Railgun Error is an unofficial HTTP status code specific to Cloudflare.

The 527 error indicates an interrupted connection between Cloudflare and the origin server's Railgun server. Railgun was a WAN optimization technology developed by Cloudflare that compressed and accelerated dynamic content delivery.

Cloudflare deprecated and discontinued the Railgun product in 2023, so this error code is largely historical.

See Also

• Cloudflare docs