Ngrok ingress rule routing for stable hostname assignment

Tunnel Hostname Persistence

Ngrok provides HTTP tunneling that automatically handles HTTPS certificates, exposing local development servers via a generated .ngrok.io address. While this facilitates rapid deployment, the default behavior assigns a random hostname upon each single-session tunnel initiation.

For teams requiring reproducibility in API integrations or webhook configurations, relying on dynamic URLs creates a configuration overhead. Although the --domain flag exists for custom domain mapping, this feature is restricted by plan-based permission boundaries, leaving a gap for developers who need stable, non-randomized hostnames without full custom domain ownership.

What are the available configuration options for ensuring a consistent hostname across restarts in the free tier? Is there a documented method to reserve a specific subdomain via the CLI or dashboard without a paid subscription?