Supported TLS Clients

ngrok's TLS endpoints are designed to work with TLS clients that fit the criteria described on this page.

SNI

TLS endpoints only work with modern TLS clients that populate the SNI extension. See the documentation on TLS Termination for additional details on compatible clients.

STARTTLS

Protocols that begin in plain text and upgrade to TLS via a mechanism like STARTTLS in SMTP, IMAP, etc are not supported. If you need to support connections which upgrade to TLS, use a TCP Endpoint.