Cursor + Asyx: From Prompt to Public Demo URL
Cursor users often ship features locally first—then need a link for a teammate, client, or CI bot. Asyx turns localhost:3000 into https://yourname.tunnel.asyx.ai from Cursor’s integrated terminal in one command after initial setup.
Prerequisites
Install the Asyx CLI and run asyx setup once on this machine. Create a free account if you have not already.
The Cursor workflow
- Prompt Cursor to build or fix a feature (React, API, full stack—anything with a dev server).
- Start the dev server in Cursor’s terminal (
npm run dev, etc.). - Open a second terminal tab in Cursor and run:
asyx tunnel --http --port 3000
- Copy the printed URL into a PR comment, Slack, or email.
While the tunnel runs and your laptop is online, reviewers see the live app over HTTPS.
Example Cursor prompt
Implement the settings page, run the dev server on port 3000, then tell me
the exact asyx tunnel command to expose it publicly. I already ran asyx setup.
Cursor should not commit ~/.asyx/ certificates or paste secrets into the repo.
Port conflicts
If port 3000 is taken, check the dev server output (Vite often uses 5173):
asyx tunnel --http --port 5173
Private previews
For client-only demos, add a Quickpass security group:
asyx tunnel --http --port 3000 --secgroup reviewers
See Quickpass for enrollment flow.
Troubleshooting in Cursor
| Issue | Fix |
|---|---|
asyx: command not found | npm install -g asyx or use npx asyx@latest |
| Browser did not open during setup | Run asyx setup again; copy the printed URL manually |
| Tunnel URL 502 / unreachable | Confirm dev server is running on the same port |
| Link dies overnight | Tunnel stops when CLI exits or machine sleeps—expected for dev previews |
Related guides
- AI Agents Overview — patterns for any coding assistant
- Agent Checklist — copy-paste steps for agents
- Publish in 60 Seconds
FAQ
Can Cursor’s agent run asyx tunnel automatically?
Yes, if agent mode has terminal access. Many teams prefer running the tunnel command themselves for visibility.
Does this work with Cursor background agents?
The machine running the agent must have asyx installed and be enrolled. Remote cloud agents without your device cert cannot open your tunnels.