Cloud infrastructure platform Vercel announced on August 14 that its Content Delivery Network (CDN) now natively supports the Encrypted Client Hello (ECH) protocol for all domains managed via Vercel DNS. Configured automatically at the platform level, this feature enhances network traffic privacy without requiring developers to manually modify their application source code.
Closing the Last HTTPS Privacy Gap
According to Vercel, Encrypted Client Hello addresses one of the final remaining privacy leaks in traditional HTTPS connections. Previously, even though data exchanged between a browser and a server was encrypted via TLS, the Server Name Indication (SNI) field sent during the initial TLS handshake remained in plaintext. This exposed the target domain name to on-path network observers—such as Internet Service Providers (ISPs) and network eavesdroppers—even if the underlying content remained confidential.
How ECH Protects Metadata on Vercel CDN
With ECH enabled, the actual SNI payload is fully encrypted before transmission. When a user establishes a connection, intermediate network monitors will only see traffic routed to Vercel's shared front-facing host, vercel-ech.com, rather than the application's true domain name. This mechanism effectively conceals the final traffic destination across Vercel's global CDN infrastructure.
Browser Support and Backward Compatibility
Vercel noted that ECH will automatically activate for users on modern browsers that support the standard, including Google Chrome, Microsoft Edge, and Mozilla Firefox. For domains not managed by Vercel DNS or requests originating from incompatible legacy browsers, the system gracefully falls back to standard TLS negotiation to ensure uninterrupted service availability.