---
title: ISO 6346 Container & Chassis Check-Digit Validator API | BIC MOD-11 Engine
description: Validate 11-character intermodal shipping container numbers (CSQU3054383), compute ISO 6346 Modulo-11 check digits, and decode 4-character size/type codes in sub-1ms.
canonical: https://stanzaapi.com/tools/container-validator/
---

[Home](/)/[API Directory](/tools/)/ISO 6346 Container & Chassis Check-Digit Validator API

 <5ms Edge Latency99.9% SLA AvailableVerified: Sep 2026V8 Pure ComputeMaritime & Intermodal Freight

# ISO 6346 Container & Chassis Check-Digit Validator API

Verify intermodal container numbers, calculate ISO 6346 MOD-11 check digits, and decode size/type codes in sub-1ms pure compute.

[Subscribe & Get API Key →](/tools/pricing)[⚡ Live Playground](#live-playground)[Specs (4)](#specifications)

 Interactive Edge Workbench

## ⚡ Live Pure-Compute Playground

 Test deterministic edge parsing with sub-2ms execution across 330+ Cloudflare V8 edge locations. Zero persistent storage, zero cold-starts, pure function $f(x)=y$.

32KB Demo Cap60 req/min Burst<2ms V8 ComputeZero Data Retention

input.txt0 B

 Reset

1

CSQU3054383

 RUN VALIDATION (<5ms) [ CHECKSUM: AWAITING RUN ]

output.jsondemo-ready

Status: Ready Copy

```
{
  "status": "Click RUN VALIDATION to execute on the Cloudflare edge..."
}
```

Sandbox Quota: Free Tier (50 reqs/mo) • Production keys from $29/mo[Get Free Sandbox Key →](/login?email=)

Need 512KB+ Payloads, High-Throughput & 99.9% Production SLA?

Direct API keys include pooled monthly quotas, zero cold-starts, and HIPAA BAA eligibility on the Mega tier.

[Get Production API Key →](/pricing)

## Key Capabilities & Performance Architecture

- ✓Complete ISO 6346 Modulo-11 check digit verification and calculation
- ✓Automated extraction of 3-letter BIC Owner Code, Equipment Identifier (U, J, Z), and Serial Number
- ✓4-character Size & Type code decoder (e.g. 22G1 = 20ft Standard, 45G1 = 40ft High Cube, 45R1 = 40ft Reefer)
- ✓Zero external subrequests, sub-1ms edge latency on Cloudflare Workers
- ✓Supports ocean containers, intermodal chassis (Z), and detachable equipment (J)

## ISO 6346 Standard Specifications (4 Specifications)

Explore full structural breakdowns, checksum logic, and field schemas for every supported format.

[BIC Bureau International des Conteneurs 3-Letter Owner Prefix Spec — Verify 3-letter BIC owner prefixes for shipping lines, container leasing companies, and rail operators. — View Specification →](/tools/container-validator/iso-6346/bic-owner-code-format)[ISO 6346 Modulo-11 Shipping Container Check Digit Formula & Step-by-Step — Step-by-step Modulo-11 check digit calculation for 11-character intermodal container numbers. — View Specification →](/tools/container-validator/iso-6346/iso-6346-check-digit-calculation)[ISO 6346 4-Character Container Size and Type Code Directory — Decode ISO 6346 4-character size and type codes into precise metric and imperial dimensions and cargo types. — View Specification →](/tools/container-validator/iso-6346/container-size-type-codes)[ISO 6346 Equipment Category Identifiers (U, J, Z) — Understand the 4th position equipment category identifier letters (U, J, Z) in container numbers. — View Specification →](/tools/container-validator/iso-6346/equipment-category-identifiers)

## API Endpoints & Request Signatures

| Method | Path | Description |
| --- | --- | --- |
| `POST` | `/api/v1/container/validate` | Validate container number check digit and decode size/type code |
| `POST` | `/api/v1/container/check-digit` | Calculate check digit for first 10 characters of container ID |

## Sample Response JSON Payload

All endpoints deliver strongly-typed envelopes with deterministic parsing and performance metrics.

HTTP 200 Response PayloadCopy

```
{
  "success": true,
  "data": {
    "valid": true,
    "containerNumber": "CSQU3054383",
    "ownerCode": "CSQ",
    "categoryIdentifier": "U (Freight Container)",
    "serialNumber": "305438",
    "checkDigit": 3,
    "checksumValid": true,
    "sizeType": {
      "code": "45G1",
      "length": "40 ft (12.192 m)",
      "height": "9 ft 6 in (2.896 m High Cube)",
      "type": "General Purpose Container with ventilation"
    }
  },
  "meta": {
    "latency_ms": 0.65,
    "version": "1.0.0"
  }
}
```

## Multi-Language Integration Code

Copy and paste ready-to-run snippets with your direct API credentials:

cURLCopy

```
curl --request POST \
  --url "https://api.stanzaapi.com/container-validator/api/v1/container/validate" \
  --header "Content-Type: application/json" \
  --header "x-api-key: YOUR_API_KEY" \
  --data '{
  "containerNumber": "CSQU3054383",
  "sizeTypeCode": "45G1"
}'
```

Node.js (Fetch)Copy

```
const response = await fetch("https://api.stanzaapi.com/container-validator/api/v1/container/validate", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "x-api-key": process.env.API_KEY || "YOUR_API_KEY"
  },
  body: JSON.stringify({
  "containerNumber": "CSQU3054383",
  "sizeTypeCode": "45G1"
})
});

const data = await response.json();
console.log(data);
```

Python (Requests)Copy

```
import requests
import json

url = "https://api.stanzaapi.com/container-validator/api/v1/container/validate"
headers = {
    "Content-Type": "application/json",
    "x-api-key": "YOUR_API_KEY"
}
payload = {
    "containerNumber": "CSQU3054383",
    "sizeTypeCode": "45G1"
}

response = requests.post(url, json=payload, headers=headers)
print(response.json())
```

GoCopy

```
package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"os"
)

func main() {
	url := "https://api.stanzaapi.com/container-validator/api/v1/container/validate"
	payload := []byte(`{"containerNumber":"CSQU3054383","sizeTypeCode":"45G1"}`)

	req, _ := http.NewRequest("POST", url, bytes.NewBuffer(payload))
	req.Header.Add("Content-Type", "application/json")
	req.Header.Add("x-api-key", os.Getenv("API_KEY"))

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)
	fmt.Println(string(body))
}
```

## Frequently Asked Questions

How is the ISO 6346 Modulo-11 check digit calculated?

Letters are converted to numbers omitting multiples of 11 (A=10, B=12... Z=38). Each of the 10 characters is multiplied by 2^position (powers of 2: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512). The sum modulo 11 equals the check digit (if remainder is 10, check digit is 0).

What do equipment category letters U, J, and Z represent?

U designates all freight containers; J designates detachable freight container-related equipment; Z designates trailers and chassis.

## Complementary Enterprise APIs

Seamlessly orchestrate data pipelines across adjacent financial, regulatory, and supply-chain protocols:

[GS1 2027 Barcode & QR Decoder → — Decode SSCC-18 pallet tags, serial logistics identifiers, and GS1 Digital Link URIs.](/tools/gs1-decoder/)[IATA Cargo & Air Waybill Validator → — Validate 11-digit AWB prefixes and airline codes for multimodal air-sea freight.](/tools/iata-validator/)[EU CBAM Carbon Importer Reporting → — Calculate emissions embedded in imported goods transported across global maritime lanes.](/tools/cbam-carbon/)