Example Response

{
  "structured": {
    "merchant": {
      "name": "Whole Foods Market",
      "address": "123 Main St, Austin TX",
      "phone": "(512) 555-0100",
      "website": null
    },
    "date": "2026-03-14",
    "time": "14:32",
    "items": [
      {
        "description": "Organic Bananas",
        "quantity": 1,
        "unitPrice": 1.99,
        "total": 1.99
      },
      {
        "description": "Almond Milk 64oz",
        "quantity": 2,
        "unitPrice": 4.49,
        "total": 8.98
      },
      {
        "description": "Sourdough Bread",
        "quantity": 1,
        "unitPrice": 5.99,
        "total": 5.99
      }
    ],
    "subtotal": 16.96,
    "tax": 0.85,
    "taxRate": "5%",
    "tip": null,
    "total": 17.81,
    "currency": "USD",
    "paymentMethod": "Visa ending 4242",
    "invoiceNumber": null,
    "category": "groceries"
  },
  "rawText": "WHOLE FOODS MARKET\n123 Main St, Austin TX\n..."
}

Step 1: Initial Request (get Invoice)

Send your base64-encoded receipt. You will receive a 402 Payment Required response with a Lightning invoice for 50 sats per page.

Request body:

{
  "document": "data:image/jpeg;base64,<your-receipt-image>"
}

Example curl command:

# Encode your receipt image
RECEIPT=$(base64 -w0 receipt.jpg)

curl -X POST https://sats4ai.com/api/l402/receipt-ocr \
-H "Content-Type: application/json" \
-d "{\"document\":\"data:image/jpeg;base64,$RECEIPT\"}" \
-i

Step 2: Pay the Lightning Invoice

Pay the 50-sat invoice with any Lightning wallet. Save the preimage your wallet provides after payment.

Step 3: Re-send with Payment Proof

Send the exact same request again with the Authorization header.

The JSON payload must be identical to Step 1.

curl -X POST https://sats4ai.com/api/l402/receipt-ocr \
-H "Content-Type: application/json" \
-H "Authorization: L402 <YOUR_MACAROON>:<YOUR_PREIMAGE>" \
-d "{\"document\":\"data:image/jpeg;base64,$RECEIPT\"}"

Easier: Use lnget

RECEIPT=$(base64 -w0 receipt.jpg)

lnget POST https://sats4ai.com/api/l402/receipt-ocr \
  --json "{\"document\":\"data:image/jpeg;base64,$RECEIPT\"}"

Python Example

import requests, base64

# Encode receipt image
with open("receipt.jpg", "rb") as f:
    img_b64 = base64.b64encode(f.read()).decode()

payload = {
    "document": f"data:image/jpeg;base64,{img_b64}"
}

# Step 1 — get invoice
r = requests.post("https://sats4ai.com/api/l402/receipt-ocr",
    json=payload,
    headers={"Content-Type": "application/json"})
# r.status_code == 402
# Parse macaroon and invoice from r.headers["www-authenticate"]

# Step 2 — pay invoice with your Lightning wallet, get preimage

# Step 3 — re-send with auth
r2 = requests.post("https://sats4ai.com/api/l402/receipt-ocr",
    json=payload,
    headers={
        "Content-Type": "application/json",
        "Authorization": "L402 <macaroon>:<preimage>"
    })
result = r2.json()
data = result["structured"]
print(f"Merchant: {data['merchant']['name']}")
print(f"Total: {data['currency']} {data['total']}")
print(f"Category: {data['category']}")
for item in data["items"]:
    print(f"  - {item['description']}: {item['total']}")

Request Parameters

Response Fields

Use Cases

• Expense tracking: snap a receipt, get structured data for your spreadsheet
• Accounting automation: extract invoice data without manual entry
• AI agents processing financial documents
• Tax preparation: categorize and total expenses from receipt photos
• Privacy-sensitive financial document processing (no data stored)