👨‍💻👨💻 Getting Started

Installation

Browsers with WebLN capabilities provide APIs using a global JavaScript variable window.webln that can be used to interact with the connected Bitcoin Lightning wallet.

⚡WebLN Providers

You don't need to add any library to your project.

Detecting WebLN support

Before you start using WebLN you need to check for browser support by checking if the variable window.webln is defined:

if (typeof window.webln !== 'undefined') {
  console.log('WebLN is available!');
}

window.webln might not be available during pageload. See the code example below for proper detection.

Detect if a WebLN provider is available

async function detectWebLNProvider(timeoutParam) {
  const timeout = timeoutParam ?? 3000;
  const interval = 100;
  let handled = false;

  return new Promise((resolve) => {
    if (window.webln) {
      handleWebLN();
    } else {
      document.addEventListener("webln:ready", handleWebLN, { once: true });
      
      let i = 0;
      const checkInterval = setInterval(function() {
        if (window.webln || i >= timeout/interval) {
          handleWebLN();
          clearInterval(checkInterval);
        }
        i++;
      }, interval);
    }

    function handleWebLN() {
      if (handled) {
        return;
      }
      handled = true;

      document.removeEventListener("webln:ready", handleWebLN);

      if (window.webln) {
        resolve(window.webln);
      } else {
        resolve(null);
      }
    }
  });
}

Enable WebLN

Before you can work with any of the WebLN APIs you need call the method enable() :

await window.webln.enable();

Depending on the used WebLN provider this will ask the user to connect their Lightning wallet with the website.

The WebLN provider will ask the user for permission to connect with your website.

You should only initiate a request in response to direct user action, such as clicking a button.

Using WebLN

Now you are ready to work with the WebLN APIs.

await window.webln.enable();
await window.webln.sendPayment();

Have a look at the the WebLN Reference for detailed explanations and usage examples for the different APIs.

WebLN Events

WebLN triggers events like webln:enabled upon enabling, allowing apps and packages to subscribe and listen to these events.

window.addEventListener("webln:enabled", () => {
    console.log("WebLN is enabled!");
});

Error handling

There are different errors that can happen while using the WebLN APIs. Make sure to handle them and let the user know what went wrong.

Error handling