21tunnel

21tunnel gives AI coding agents like Claude Code, Cursor, and Devin scoped, short-lived credentials to open secure public tunnels to localhost, with one-click cascade revoke.

Also a complete open-source ngrok alternative in Rust: HTTP, TCP, SSH and gRPC tunnels, sticky subdomains, custom domains on the free tier, live request inspector, and team RBAC with audit logs. Self-hostable free forever under MIT and Apache-2.0.