HTTP Tunnels

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ngrok HTTP tunnels allow you to route HTTP protocols quickly and easily. These include websites, RESTful APIs, web servers, websockets, and much more.

Starting an HTTP tunnel is a easy as ngrok http 80, or whatever local port your service is running on. For a full list of options for starting HTTP tunnels, see our ngrok agent HTTP Tunnel reference.

Custom subdomains

ngrok assigns random names to the HTTP tunnels it opens for you. This is okay for one-time personal uses. But if you're displaying the URL at a hackathon or integrating with a third-party webhook, it can be frustrating if the tunnel name changes or is difficult to read. You can specify a custom domain for your tunnel URL with the --domain switch.

Example: Open a tunnel with the domain 'inconshreveable.ngrok.dev'

ngrok http --domain=inconshreveable.ngrok.dev 80

Password protecting your tunnel with Basic Auth

Anyone who can guess your tunnel URL can access your local web server unless you protect it with a password. You can make your tunnels secure with the --basic-auth flag. This enforces HTTP Basic Auth on all requests with the username and password you specify as an argument. You can include multiple --basic-auth flags to allow multiple users.

Example: Password-protect your tunnel

ngrok http --basic-auth="username:password" 8080

Tunnels on custom branded domains

Instead of your tunnel appearing as a subdomain of an ngrok owned domain, you can connect ngrok tunnels to your custom domains. To run a tunnel over dev.example.com, follow these steps:

1. Navigate to the Domains tab of your ngrok.com dashboard and click 'Add a domain'. Enter dev.example.com as a Reserved Domain. This guarantees that no one else can hijack your domain name with their own tunnel.

2. On your dashboard, click on the 'CNAME' icon to copy your CNAME target.

   

3. Create a DNS CNAME record from dev.example.com to your CNAME target. In this example, we would point the CNAME record to 2w9c34maz.wdv31sd.ngrok-cname.com

4. Invoke ngrok with the --domain switch and specify the name of your custom domain as an argument.

   Example: Run a tunnel over a custom domain

   ngrok http --domain=dev.example.com 8000

Local HTTPS servers

ngrok assumes that the server it is forwarding to is listening for unencrypted HTTP traffic, but if your server is listening for encrypted HTTPS traffic, you can specify a URL with an https:// scheme to request that ngrok speak HTTPS to your local server.

Forward to an https server by specifying the https:// scheme

ngrok http https://localhost:8443

As a special case, ngrok assumes that if you forward to port 443 on any host that it should send HTTPS traffic and will act as if you specified an https:// URL.

Forward to the default https port on localhost

ngrok http 443

ngrok assumes that your local network is private and it does not do any validation of the TLS certificate presented by your local server.

Rewriting the Host header

When forwarding to a local port, ngrok does not modify the tunneled HTTP requests at all, they are copied to your server byte-for-byte as they are received. Some application servers like WAMP and MAMP and use the Host header for determining which development site to display. For this reason, ngrok can rewrite your requests with a modified Host header. Use the --host-header switch to rewrite incoming HTTP requests.

If rewrite is specified, the Host header will be rewritten to match the hostname portion of the forwarding address. Any other value will cause the Host header to be rewritten to that value.

Rewrite the Host header to 'site.dev'

ngrok http --host-header=rewrite site.dev:80

Rewrite the Host header to 'example.com'

ngrok http --host-header=example.com 80

Serving local directories with ngrok's built-in file server

ngrok can serve local file system directories by using its own built-in file server, no separate server needed. You can serve files using the file:// scheme when specifying the forwarding URL.

All paths must be specified as absolute paths, the file:// URL scheme has no notion of relative paths.

Share a folder on your computer with authentication

ngrok http --basic-auth="user:password" file:///Users/alan/share

File URLs can look a little weird on Windows, but they work the same:

Share a folder on your Windows computer

ngrok http "file:///C:\Users\alan\Public Folder"

Tunneling to HTTP or HTTPS only

By default, when ngrok runs an HTTP tunnel, it opens endpoints for both HTTP and HTTPS traffic. If you wish to only forward HTTP or HTTPS traffic, but not both, you can toggle this behavior with the --scheme flag.

Example: Only listen on an HTTP tunnel endpoint

ngrok http --scheme=http site.dev:80

Example: Only listen on an HTTPS tunnel endpoint

ngrok http --scheme=https site.dev:80

HTTP Tunnel Examples

ngrok http 8080                             # forwards provided ngrok URL to port 80
ngrok http example.com:9000                 # forward traffic to example.com:9000
ngrok http --domain=bar.ngrok.dev 80        # request subdomain name: 'bar.ngrok.dev'
ngrok http --domain=www.ex.com 1234         # request tunnel 'www.ex.com' (DNS CNAME)
ngrok http --basic-auth='falken:joshua' 80  # enforce basic auth on tunnel endpoint
ngrok http --host-header=ex.com 80          # rewrite the Host header to 'ex.com'
ngrok http file:///var/log                  # serve local files in /var/log
ngrok http https://localhost:8443           # forward to a local https server

HTTP Tunnel Configuration Options

For a full list of options for configuring HTTP tunnels, see our ngrok agent HTTP Tunnel reference.