> ## Documentation Index
> Fetch the complete documentation index at: https://lnurl.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# LUD-02: `channelRequest` base spec.

> Display inline code and code blocks

`author: akumaigorodski`

## Incoming payment channel request

Suppose user has a balance on a certain service which he wishes to turn into an incoming channel and service supports such functionality. This would require many parameters, so the resulting QR may be overly dense and cause scanning issues. Additionally, the user has must ensure that a connection to target LN node is established before an incoming channel is requested.

### Wallet to service interaction flow:

1. User scans a LNURL QR code or accesses an `lightning:LNURL..` link with `LN WALLET` and `LN WALLET` decodes LNURL.

2. `LN WALLET` makes a GET request to `LN SERVICE` using the decoded LNURL.

3. `LN WALLET` gets JSON response from `LN SERVICE` of form:

   ```Typescript theme={null}
   {
       "uri": string, // Remote node address of form node_key@ip_address:port_number
       "callback": string, // a second-level URL which would initiate an OpenChannel message from target LN node
       "k1": string, // random or non-random string to identify the user's LN WALLET when using the callback URL
       "tag": "channelRequest" // type of LNURL
   }
   ```

   or

   ```
   {"status": "ERROR", "reason": "error details..."}
   ```

4. `LN WALLET` opens a connection to the target node using `uri` field.

5. `LN WALLET` issues a GET request to `LN SERVICE` using `<callback><?/&>k1=<k1>&remoteid=<Local LN node ID>&private=<1/0>` if user decides to proceed or `<callback><?/&>k1=<k1>&remoteid=<Local LN node ID>&cancel=1` if user decides to cancel a channel midway.

6. `LN SERVICE` sends a `{"status": "OK"}` or `{"status": "ERROR", "reason": "error details..."}` JSON response.

7. `LN WALLET` awaits for incoming `OpenChannel` message from the target node, which would initiate a channel opening.