L402 Extract Document API

L402 API

Pay with Bitcoin, get AI results. Copy-paste the commands below.

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Before You Start

Lightning Wallet

Phoenix, Muun, Wallet of Satoshi, Alby, or any LN wallet. Agents: CLW

Terminal or Tool

A command line, Postman, or lnget (recommended)

Private & No Signup

No account, no subscription, no personal data. Pay only when you use it

Want to try this without a terminal? Use Document Extraction on the web — pay with any Lightning wallet, no setup needed.

Using the L402 OCR API

Extract text from PDFs, images, and scanned documents. Returns clean Markdown with tables, headers, and formatting preserved.

Price: 10 Sats per page · Supported formats: PDF, PNG, JPEG, TIFF, WebP, BMP

API Endpoint: https://sats4ai.com/api/l402/extract-document

Quickest: Use lnget

lnget handles the full L402 flow automatically — one command, payment included.

# Extract text from a PDF (easiest method)
DOC=$(base64 -w0 invoice.pdf)
lnget -X POST https://sats4ai.com/api/l402/extract-document \
  -H "Content-Type: application/json" \
  -d "{\"document\": \"data:application/pdf;base64,$DOC\"}"

Step 1: Initial Request

Send the document as a base64 data URI. You will receive a 402 Payment Required response.

curl -X POST https://sats4ai.com/api/l402/extract-document \
-H "Content-Type: application/json" \
-d '{
  "document": "data:application/pdf;base64,JVBERi0xLjQg..."
}' \
-i

Expected Response Headers:

www-authenticate: L402 macaroon="<YOUR_MACAROON>", invoice="<LIGHTNING_INVOICE>"

Step 2: Pay the Lightning Invoice

Pay the invoice with any Lightning wallet and save the preimage (proof of payment).

Step 3: Final Request

Send the exact same request with the Authorization header.

Important: The JSON payload must be identical to Step 1.

curl -X POST https://sats4ai.com/api/l402/extract-document \
-H "Content-Type: application/json" \
-H "Authorization: L402 <YOUR_MACAROON_STRING_HERE>:<YOUR_PREIMAGE_HERE>" \
-d '{
  "document": "data:application/pdf;base64,JVBERi0xLjQg..."
}'

Expected Successful Response:

{
  "content": "# Invoice\n\n| Item | Price |\n|------|-------|\n| Widget | $9.99 |\n\nThank you for your purchase.",
  "pages": 1
}

Request Body Parameters

`document`: string (required)

Base64-encoded document as a data URI. Use data:application/pdf;base64,... for PDFs or data:image/png;base64,... for images. If no prefix is provided, PDF is assumed.

`modelId`: number or string (optional)

Omit for the best default model. See available models.

Response Format

content: Extracted text in Markdown format. Tables are rendered as Markdown tables, headers preserved, page breaks marked with ---.

pages: Number of pages processed.