SSCC Validation in Python — GS1 Serial Shipping Container Code Explained

1. What is an SSCC?

The Serial Shipping Container Code (SSCC) is an 18-digit identifier defined by GS1 for tracking logistics units — pallets, parcels, cases, and containers — as they move through the supply chain. It is the globally unique "licence plate" for any physical shipment.

SSCCs are assigned by the company that creates the logistics unit (the packer, manufacturer, or 3PL). Once assigned, the SSCC follows the unit from origin to destination, appearing in advance shipping notices (ASN), warehouse management systems (WMS), and transport management systems (TMS).

The standard is part of the GS1 system and is encoded in GS1-128 barcodes using Application Identifier (AI) 00. It is widely used in retail, healthcare, automotive, and general logistics.

2. SSCC structure — 18 digits decoded

An SSCC has exactly 18 digits, split into three logical parts:

3. The GS1 check digit algorithm

The SSCC uses the same mod-10 check digit algorithm as EAN, GTIN, and GLN — alternating weights of 3 and 1, applied from right to left (or equivalently, the leftmost digit of the 17 data digits gets weight 3).

Let's walk through 106141411234567897:

# sscc_check_digit.py — GS1 mod-10 check digit for SSCC
import re


def validate_sscc(raw: str) -> bool:
    digits = raw.replace(" ", "").replace("-", "")
    if not re.match(r"^\d{18}$", digits):
        return False

    total = sum(
        int(digits[i]) * (3 if i % 2 == 0 else 1)
        for i in range(17)
    )

    check_digit = (10 - (total % 10)) % 10
    return check_digit == int(digits[17])


print(validate_sscc("106141411234567897"))  # True  ✓
print(validate_sscc("106141411234567890"))  # False ✗ wrong check digit
print(validate_sscc("340123450000000018"))  # checks dynamically

4. Why SSCC validation matters

5. The production-ready solution

The IsValid SSCC API validates the format, computes the GS1 mod-10 check digit, and returns the parsed components — extension digit, company prefix with serial reference, and check digit — in a single call.

Full parameter reference and response schema: SSCC Validation API docs →

6. Python code example

Using the isvalid-sdk package or the requests library. Install with pip install isvalid-sdk or pip install requests.

# sscc_validator.py
import os
from isvalid_sdk import IsValidConfig, create_client

iv = create_client(IsValidConfig(api_key=os.environ["ISVALID_API_KEY"]))

result = iv.sscc("106141411234567897")

if not result["valid"]:
    print("Invalid SSCC")
else:
    print(f"Extension digit: {result['extensionDigit']}")     # → '1'
    print(f"Company + Serial: {result['companyAndSerial']}")  # → '0614141123456789'
    print(f"Check digit: {result['checkDigit']}")             # → '7'

# Validate SSCCs in an inbound ASN before warehouse receipt
def process_asn(pallets: list[dict]) -> list[dict]:
    results = []

    for pallet in pallets:
        if not pallet.get("sscc"):
            results.append({**pallet, "status": "missing"})
            continue

        check = validate_sscc(pallet["sscc"])

        if not check["valid"]:
            results.append({**pallet, "status": "invalid"})
            continue

        results.append({
            **pallet,
            "sscc": pallet["sscc"].replace(" ", "").replace("-", ""),
            "extension_digit": check["extensionDigit"],
            "company_and_serial": check["companyAndSerial"],
            "status": "valid",
        })

    return results

7. cURL example

Validate a valid SSCC:

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/sscc?value=106141411234567897"

Validate an SSCC with an incorrect check digit:

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/sscc?value=106141411234567890"

Validate an SSCC with extension digit 0:

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/sscc?value=006141411234567893"

8. Understanding the response

Valid SSCC:

{
  "valid": true,
  "extensionDigit": "1",
  "companyAndSerial": "0614141123456789",
  "checkDigit": "7"
}

Invalid SSCC:

{
  "valid": false
}

9. Edge cases — extension digits, GS1-128, and AI 00

# Strip AI 00 prefix from GS1-128 barcode scan
def extract_sscc(scan: str) -> str:
    # GS1-128 scan may include AI: "00106141411234567897"
    if scan.startswith("00") and len(scan) == 20:
        return scan[2:]  # remove AI 00
    return scan  # already 18 digits