Container OCR API ISO 6346 Shipping Container Number Extraction

Streamline your logistics and port operations with our Container OCR API. We provide highly accurate extraction of the standard 11-character ISO 6346 shipping container numbers from images. The engine automatically parses the owner code (BIC), equipment category, serial number, and check digit, performing strict mathematical validation to ensure absolute data reliability for your Terminal Operating Systems (TOS) or yard management workflows.

Port Automation
Freight Tracking
Yard Management

Endpoint

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

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 shipping container image. 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 separates the standard ISO 6346 components.

Field	Description
container_number	The full 11-character ISO 6346 container identification sequence.
is_valid	Boolean indicating if the check digit math validates correctly against the ISO 6346 standard algorithm.
confidence	The confidence level of the recognition (High, Medium, Low).
parsed.owner_code	The 3-letter Owner Code (BIC code) identifying the principal operator.
parsed.category	The 1-letter Equipment Category Identifier (typically 'U' for freight containers, 'J', or 'Z').
parsed.serial_number	The 6-digit Serial Number assigned by the owner.
parsed.check_digit	The 1-digit Check Digit used to validate the entire container number.

Code Examples

Request Implementation

curl -X POST https://api.structocr.com/v1/container \
  -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": {
    "container_number": "ZCSU8921655",
    "is_valid": true,
    "confidence": "High",
    "parsed": {
      "owner_code": "ZCS",
      "category": "U",
      "serial_number": "892165",
      "check_digit": "5"
    }
  }
}

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