Overview [ Documentation]
Dev Tunnels are a Visual Studio 2022 feature that create ad-hoc connections between machines that cannot directly connect to one another. A URL is created that enables any device with an internet connection to connect to the ASP.NET Core project while it runs on localhost.
Uses:
- Testing a web app on other devices
- Testing an app with external services
- Making an app temporarily available for presentation
Tunnel Options
Tunnel types:
- Temporary tunnels get a new URL each time Visual Studio is started.
- Persistent tunnels get the same URL each time Visual Studio is started.
Tunnel access:
- Private — the tunnel is only accessible on the account that created it
- Organization — the tunnel is accessible to accounts in the same organization as the one that created it
- Note: If Organization is selected for a personal Microsoft account, this has the same effect as Private
- Public — anyone can access the tunnel
Creating Dev Tunnels
Visual Studio > Debug toolbar > Web server control dropdown > Dev Tunnels > Create A Tunnel…
Enter a name, tunnel type, and tunnel access. Click OK. A web browser will open to the tunnel URL.
Tip: select the QR Code icon on the browser’s URL bar to create a QR code to the tunnel.
Dev Tunnels Tool Window
View > Other Windows > Dev Tunnels
- Clear Active Tunnel — disables a tunnel
- Make Active Tunnel — enables a tunnel
- Copy Tunnel Access Token — copies the active tunnel’s access token to the clipboard
Tunnel Access Tokens
When a tunnel is created with Private or Organization access, and the app is a web API, the token must be provided to authenticate to the tunnel. Include the following header in the request:
X-Tunnel-Authorization tunnel <TOKEN>
Tunnel URL Environment Variables
When an app is launched that uses a tunnel, Visual Studio creates the VS_TUNNEL_URL environment variable.
If there are multiple ASP.NET Core projects configured as the startup project, for all subsequent projects after the first, the variable name is VS_TUNNEL_URL_{ProjectName}.