Fiat Bridge Extension for LNbits

A public bridge that allows external websites to request Stripe checkout sessions using your LNbits wallet without exposing your admin keys.

How it Works

The Fiat Bridge acts as a secure intermediary between your website and the Stripe payment gateway, leveraging LNbits' core payment engine.

1. API Call: Your website makes a simple POST request to the Fiat Bridge API endpoint using an Invoice Key.
2. Bridge Request: The extension receives the request and forwards it to the Stripe API.
3. Checkout Redirection: Stripe generates a checkout session and returns a URL. The Fiat Bridge passes this checkout_url back to your website.
4. User Payment: Your website redirects the user to the Stripe checkout page where they complete the card payment.
5. Return: After a successful checkout, the user is automatically sent back to your specified success_url.
6. Backend Fulfillment:
   • The transaction is tracked and memoed within LNbits.
   • The bitcoin equivalent (at the time of payment) is deposited into the LNbits wallet associated with the used Invoice Key.

Use Cases

The Fiat Bridge is ideal for scenarios where you want to accept legacy card payments while keeping your accounting and settlement in Bitcoin/LNbits.

• Simple Web Shops: Sell digital or physical goods on a custom website. Users pay with cards, and you receive Bitcoin instantly in your LNbits wallet.
• Physical Kiosks: Use a tablet or phone as a point-of-sale terminal. Generate a checkout link for the customer to pay on their own device via Stripe.
• Donation Platforms: Let supporters contribute via familiar card payments. The bridge handles the conversion and deposits sats into your specified wallet.
• Service Providers: Invoice clients for services (consulting, design, etc.) and receive payment in Bitcoin without them needing to know how to use a Lightning wallet.
• Secure Backend Integration: Integrate card payments into your app without ever touching sensitive Stripe API keys or card data on your own frontend.

Transitioning to a Bitcoin Standard

The Fiat Bridge is more than just a payment gateway; it's a strategic tool for businesses and individuals moving towards a Bitcoin standard:

• Immediate Settlement in Sats: Avoid the volatility and delays of legacy banking. Every card payment is converted and settled instantly in your own Bitcoin wallet.
• Legacy Compatibility: Onboard customers who aren't yet ready for Lightning by providing a familiar checkout experience (Stripe), while you benefit from Bitcoin's superior monetary properties.
• Reduced Banking Dependency: Minimize the amount of capital held in traditional financial institutions. Use Bitcoin as your primary unit of account and store of value.
• Seamless Accounting: Consolidate all your sales—whether via Lightning or Card—into a single LNbits dashboard, simplifying your financial tracking and reporting.

Installation

1. Copy this fiatbridge folder into your LNbits lnbits/extensions/ directory.
2. Restart LNbits.
3. Enable "Fiat Bridge" in the extensions list.

How to Use

1. Go to the Fiat Bridge dashboard in LNbits.
2. Copy your Invoice Key.
3. From your website's backend (or a secure bridge), send a POST request:

Endpoint: https://your-lnbits.com/fiatbridge/api/v1/checkout Headers: X-Api-Key: <your_invoice_key>

Body:

{
  "amount": 10.00,
  "memo": "Payment for Coffee",
  "success_url": "https://yourshop.com/success",
  "cancel_url": "https://yourshop.com/cancel"
}

The API will return a checkout_url which you can use to redirect the user to Stripe.