VIN OCR

Seamlessly automate vehicle verification with our enterprise-grade VIN OCR API. We provide high-precision extraction for 17-character Vehicle Identification Numbers from windshields, door jamb stickers, and metal plates. The engine features built-in ISO 3779 logic to automatically correct common OCR errors (e.g., converting 'I' to '1', 'Q' to '0') and ensure data validity for your insurance or fleet management workflows.

Endpoint

POSThttps://api.structocr.com/v1/vin

Request Parameters

Important: This endpoint requires application/json Content-Type. Images must be sent as Base64 strings.

Parameter	In	Required	Description
x-api-key	Header	Required	Your unique API key generated from the dashboard.
Content-Type	Header	Required	Must be set to `application/json`.
img	Body (JSON)	Required	The Base64 encoded string of the vehicle image (windshield, sticker, etc). Supports standard Data URI (e.g., `data:image/jpeg;base64,...`) Supports raw Base64 strings Max file size: 4.5MB Formats: JPG, PNG, WebP

Response Schema

The following fields are extracted into the data object. The engine automatically normalizes characters (e.g. upper-case).

Field	Description
vin	The 17-character Vehicle Identification Number (ISO 3779 corrected).
confidence	The confidence level of the recognition (High, Medium, Low).
carrier_type	The detected location of the VIN (e.g., 'windshield', 'sticker_label', 'metal_plate').

Code Examples

Request Implementation

curl -X POST https://api.structocr.com/v1/vin \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_API_KEY" \
  -d '{
    "img": "data:image/jpeg;base64,/9j/4AAQSkZJRg..."
  }'

Success Response (200 OK)

JSON EXAMPLE

{
  "success": true,
  "data": {
    "vin": "1M8GDM9A6KP042788",
    "confidence": "High",
    "carrier_type": "windshield"
  }
}

Error Responses

400 Bad Request - Invalid Input

Returned when JSON is invalid or image data is missing/corrupt.

{
  "status": 400,
  "code": "INVALID_REQUEST_FORMAT",  
  // or "INVALID_JSON", "INVALID_BASE64_FORMAT"
  "message":"The image data in 'img' field is malformed. Please check for illegal characters (spaces, newlines) or incorrect Base64 encoding."
}

402 Payment Required - Insufficient Credits

{
  "status": 402,
  "code": "INSUFFICIENT_CREDITS",
  "message": "Your account balance is insufficient to complete this operation."
}

413 Payload Too Large

The Base64 decoded image size exceeds 4.5MB.

{
  "error": "FILE_TOO_LARGE"
}

415 Unsupported Media Type

{
  "error": "INVALID_CONTENT_TYPE_USE_JSON"
}

422 Unprocessable Entity - Policy Violation

{
  "status": 422,
  "code": "CONTENT_POLICY_VIOLATION",
  "message": "The document content could not be processed due to safety policies."
}

500 Internal Server Error

{
  "status": 500,
  "code": "PROCESSING_ERROR",
  "message": "An internal error occurred while processing the document..."
}

503 Service Unavailable - System Busy

{
  "status": 503,
  "code": "SYSTEM_BUSY",
  "message": "StructOCR is currently processing a high volume of requests..."
}

Status Code Definitions

Code	Error Code	Description
200	SUCCESS	Recognition success
400	INVALID_REQUEST_FORMAT	Invalid payload or corrupted Base64. Ensure the image string has no whitespace, newlines, or illegal characters.
402	INSUFFICIENT_CREDITS	Account balance too low
413	FILE_TOO_LARGE	Decoded image exceeds 4.5MB
415	INVALID_CONTENT_TYPE	Not using application/json
422	CONTENT_POLICY_VIOLATION	AI safety/policy block
503	SYSTEM_BUSY	API Rate limit reached