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L402 Microtransactions

L402 enables pay-per-request API monetization using the Lightning Network. Users pay a Lightning invoice to access your API - no accounts, no subscriptions, no credit cards required.

OpenNode KYC Required

L402 requires production OpenNode credentials because users pay real satoshis. Complete KYC verification before deploying L402 endpoints. Learn more

What is L402?​

L402 (formerly LSAT) combines:

  • HTTP 402 Payment Required - The web's native payment status code
  • Lightning Network - Instant Bitcoin micropayments
  • Macaroons - Cryptographic bearer tokens with permissions

The Problem​

Traditional API monetization requires:

  • User accounts and passwords
  • Credit cards on file
  • Monthly subscriptions (even for light usage)
  • Complex billing infrastructure
  • Fraud prevention systems

The Solution​

With L402:

  • No accounts - Pay and access immediately
  • No credit cards - Bitcoin only
  • Pay-per-use - Only pay for what you consume
  • Instant access - Payment confirms in ~1 second
  • Global - Anyone with Bitcoin can access

How It Works​

1. Client requests API                    2. Server returns 402
   ─────────────────────────────>           <─────────────────────
   GET /api/premium/data                    HTTP 402 Payment Required
                                            Invoice: lnbc100n1p...
                                            Macaroon: AgEL...

3. Client pays invoice                    4. Client retries with proof
   ─────────────────────>                    ─────────────────────────>
   Via Lightning wallet                      Authorization: L402 mac:preimage
   (~1 second)
                                          5. Server verifies, grants access
                                             <─────────────────────────
                                             HTTP 200 OK
                                             { "data": "..." }

Key Benefits​

Traditional APIL402 API
Account requiredNo account needed
Credit card on fileNo payment method stored
Monthly subscriptionPay per request
Minimum $5-20 chargeAs low as 1 sat (~$0.0004)
Chargeback riskImpossible to reverse
KYC for usersPermissionless access

Use Cases​

AI API Monetization​

Charge per API call for AI services:

{
  "endpoints": [
    { "path": "/api/ai/gpt4", "price": 500 },
    { "path": "/api/ai/dalle", "price": 1000 },
    { "path": "/api/ai/whisper", "price": 100 }
  ]
}

Premium Content​

Unlock articles, reports, or media:

{
  "endpoints": [
    { "path": "/api/articles/premium/*", "price": 50 },
    { "path": "/api/reports/*", "price": 500 }
  ]
}

Data APIs​

Pay-per-query data access:

{
  "endpoints": [
    { "path": "/api/market-data/*", "price": 10 },
    { "path": "/api/analytics/*", "price": 25 }
  ]
}

Proxy Monetization​

Monetize third-party APIs you have access to:

{
  "proxy": {
    "name": "Premium Weather API",
    "target": "https://api.weather.com",
    "price": 5
  }
}

Quick Example​

Request Without Payment​

curl https://api.yourservice.com/api/premium/data

Response: 402 Payment Required

{
  "error": "Payment Required",
  "l402": {
    "macaroon": "AgELbGlnaHRuaW5nLWVuYWJsZQ...",
    "invoice": "lnbc100n1p3...",
    "amount_sats": 100,
    "payment_hash": "abc123..."
  }
}

Pay the Invoice​

Use any Lightning wallet (Phoenix, Muun, Zeus, etc.) to pay. Get the preimage.

Request With Payment Proof​

curl https://api.yourservice.com/api/premium/data \
  -H "Authorization: L402 AgELbGlnaHRuaW5nLWVuYWJsZQ...:abc123def456..."

Response: 200 OK

{
  "data": "Premium content here..."
}

Pricing​

L402 Microtransactions: $299/month

Includes everything in Standalone API plus:

  • L402 protocol support
  • Pay-per-request billing
  • Usage metering dashboard
  • White-glove onboarding

OpenNode charges 1% per transaction for payment processing (paid directly to OpenNode).

For standalone REST API, see Standalone API ($199/mo). For Kentico sites, see Kentico Commerce ($249/mo).

Architecture​

Lightning Enable handles the complexity:

+-----------------+
| Your API        |
| (Protected)     |
+--------+--------+
         |
         v
+--------+--------+      +------------------+      +-----------+
| L402 Middleware |----->| Lightning Enable |----->| OpenNode  |
| (Auth Check)    |      | (Invoice/Verify) |      | (Payment) |
+-----------------+      +------------------+      +-----------+
         |
         | If valid L402 credential
         v
+-----------------+
| Your API Logic  |
| (Execute)       |
+-----------------+

Getting Started​

  1. Enable L402 in your Lightning Enable configuration
  2. Configure protected paths that require payment
  3. Set pricing per endpoint
  4. Test with a Lightning wallet
  5. Deploy to production

Next Steps​

Resources​