Run multiple tunnels at once

Expose several local services from one machine — either via separate invocations or a single tunnels.yaml file.

You want to expose more than one local port at the same time. Common cases: a frontend on :3000 plus an API on :8080, or a webhook receiver on one subdomain plus a preview build on another.

JustTunnel supports two ways to do this: run several justtunnel processes in parallel, or declare them all in a tunnels.yaml file and let one process manage them. Both honor your plan's tunnel limit.

Option 1: separate invocations

The simplest path: one terminal pane (or tmux window) per tunnel.

1. Start each tunnel in its own shell

justtunnel 3000

justtunnel 8080

Each call opens an independent tunnel with its own subdomain. They do not interfere with each other; killing one with Ctrl-C does not affect the other.

2. Optionally pin subdomains

justtunnel 3000 --subdomain acme-frontend

justtunnel 8080 --subdomain acme-api

See Reserve a custom subdomain for the rules around reserved names.

Option 2: one process, `tunnels.yaml`

If you'd rather manage everything from a single shell — and you want hot-reload when you edit the file — use --config-file.

1. Write a `tunnels.yaml`

tunnels:
  - port: 3000
    name: frontend
    subdomain: acme-frontend
  - port: 8080
    name: api
    subdomain: acme-api

Each entry needs a port. name, subdomain, and password are optional.

2. Start the multi-tunnel session

justtunnel --config-file tunnels.yaml

When stdout is a terminal, the CLI launches a TUI that shows every tunnel side-by-side, with per-tunnel request logs and connection state. The file is watched for changes — adding or removing entries triggers a hot reload without restarting the process. Full details are in Use a tunnels.yaml config file.

3. Mix and match

You can pass a port arg AND a config file at the same time. The port arg becomes one extra tunnel on top of whatever the file declares:

justtunnel 3000 --config-file tunnels.yaml

Duplicate ports are deduped — if 3000 is already in tunnels.yaml, the CLI uses the file's entry and ignores the duplicate.

Verify

After starting the tunnels, hit each public URL:

curl -I https://acme-frontend.justtunnel.dev
curl -I https://acme-api.justtunnel.dev

Each should return HTTP/2 200 (or whatever your local service returns). In the TUI you'll see the request logged on the matching tunnel pane.

If your account is on the free plan and you exceed the tunnel limit, the extra tunnel is rejected with a clear plan-limit error — see Plans and limits.

Common issues

Plan tunnel limit reached. Free-plan accounts cap at 1 concurrent tunnel; the second one fails. Upgrade or close the first tunnel.
Port collision in tunnels.yaml. Duplicate port entries fail validation: tunnel[N]: duplicate port <P>. Each port must be unique.
Subdomain collision across entries. Two tunnels cannot share a subdomain, even on the same account. Pick distinct names.

Use a tunnels.yaml config file — full reference for the YAML schema and hot-reload behavior.
Reserve a custom subdomain — pin stable URLs for each tunnel.
Plans and limits — concurrent-tunnel caps per plan.
justtunnel [port] — root command reference.