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ISO 6346 / BIC Container Prefix Coding <1ms Edge Edge Compute

ISO 6346 Equipment Category Identifiers (U, J, Z)

Understand the 4th position equipment category identifier letters (U, J, Z) in container numbers. This specification documents the exact field layout, checksum rules, and validation behavior so your integration matches ISO 6346 / BIC Container Prefix Coding without reading the source standard.

Latency: <1ms Edge Availability: 99.99% Standard: ISO 6346 Clause 2.1 In-Memory Execution
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{
  "status": "Click RUN VALIDATION to execute on the Cloudflare edge..."
}
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Official Standard & Validation Protocol Authority: Bureau International des Conteneurs (BIC) & ISO ↗

Quick Summary: Understand the 4th position equipment category identifier letters (U, J, Z) in container numbers. Validates strictly against ISO 6346 / BIC Container Prefix Coding with sub-5ms in-memory response times.

Latency
<1ms Edge
Standard
ISO 6346 Clause 2.1
Version
Max Payload
512 KB
Privacy
In-Memory (0 bytes stored)

Specification & Structural Breakdown

Technical Summary: Validates strictly against ISO 6346 / BIC Container Prefix Coding. Payloads are parsed in memory and return clean, typed JSON in milliseconds with zero data logged.

Position 4 in any valid 11-character ISO container number must be one of three accredited uppercase letters: U, J, or Z.

IdentifierEquipment TypeDescription
UFreight ContainerAll general cargo, reefer, tank, open-top, and flat-rack containers
JDetachable EquipmentClip-on generator sets (gensets), refrigeration units, detachable tanks
ZTrailers & ChassisIntermodal chassis, skeletal trailers, and bogies

Parsed JSON Response Model

The edge microservice transforms input payloads into strongly-typed hierarchical JSON envelopes with sub-5ms latency:

HTTP 200 JSON Response Envelope
{
  "category": "U",
  "description": "Freight Container",
  "valid": true
}

Copy-Paste Integration Code (6 Languages)

Integrate ISO 6346 Equipment Category Identifiers (U, J, Z) directly into your production application with native, zero-dependency code snippets in cURL, Node.js, Python, Go, C#, and a ready-to-paste Claude prompt. Get a free API key → (no credit card required):

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"
}'
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);
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())
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))
}
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        using var client = new HttpClient();
        client.DefaultRequestHeaders.Add("x-api-key", Environment.GetEnvironmentVariable("API_KEY") ?? "YOUR_API_KEY");

        var json = @"{""containerNumber"":""CSQU3054383"",""sizeTypeCode"":""45G1""}";
        var payload = new StringContent(json, Encoding.UTF8, "application/json");

        var response = await client.PostAsync("https://api.stanzaapi.com/container-validator/api/v1/container/validate", payload);
        var content = await response.Content.ReadAsStringAsync();
        Console.WriteLine(content);
    }
}
Integrate the StanzaAPI container-validator micro-API.

Endpoint: POST https://api.stanzaapi.com/container-validator/api/v1/container/validate
Auth header: x-api-key: YOUR_API_KEY
Content-Type: application/json
Request body:
{
  "containerNumber": "CSQU3054383",
  "sizeTypeCode": "45G1"
}

Rules:
- Send the request with a 2-second timeout.
- Parse the standard envelope { success, data, meta: { latency_ms, version } }.
- On failure, read { success: false, error, code } and branch on the code.
- Do not retry 4xx responses; surface the error code to the caller.
- Treat invalid-but-well-formed payloads as HTTP 200 with data.valid === false.

Frequently Asked Questions & Technical Notes

Are numbers with category identifiers other than U, J, or Z valid under ISO 6346?

No, any 4th character other than U, J, or Z is non-compliant with ISO 6346.

Related ISO 6346 Container & Chassis Check-Digit Validator API Formats

Explore sibling specifications and standards in the same developer cluster:

Complementary Enterprise APIs

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

All ISO 6346 Container & Chassis Check-Digit Validator API Formats & Specifications (4) Directory Index ↓
BIC Bureau International des Conteneurs 3-Letter Owner Prefix Spec ISO 6346 Modulo-11 Shipping Container Check Digit Formula & Step-by-Step ISO 6346 4-Character Container Size and Type Code Directory ISO 6346 Equipment Category Identifiers (U, J, Z)