{
  "summary": "Fill a PDF template with employee onboarding data",
  "description": "Example request to POST /api/v1/fill/{pdfTemplateID}.pdf filling a W-4 style employee form.",
  "request": {
    "method": "POST",
    "url": "https://app.useanvil.com/api/v1/fill/abc123.pdf",
    "headers": {
      "Content-Type": "application/json",
      "Authorization": "Basic YOUR_BASE64_ENCODED_API_KEY"
    },
    "body": {
      "title": "Employee W-4 - Jane Smith",
      "fontSize": 10,
      "textColor": "#3E3E57",
      "alignment": "left",
      "data": {
        "employeeName": "Jane Smith",
        "socialSecurityNumber": "***-**-1234",
        "address": "123 Main St",
        "city": "San Francisco",
        "state": "CA",
        "zip": "94105",
        "filingStatus": "Single",
        "date": "2026-06-13",
        "signature": "Jane Smith"
      }
    }
  },
  "response": {
    "status": 200,
    "headers": {
      "Content-Type": "application/pdf"
    },
    "body": "<binary PDF bytes>"
  }
}