QR & Barcode
API Documentation

Overview

The QR & Barcode API generates QR codes and linear barcodes from JSON requests. QR codes support scale, border, error-correction level, and custom dark/light colors; linear barcodes support module width/height and font size. Output is available as PNG, SVG, or Base64. The batch endpoint produces a ZIP file of up to 50 generated codes in a single call.

Base URL & Authentication

Base URL

https://api.chemhub.com/api/v1

Authentication

Include your API credentials in every request header.

X-API-Key: your_api_key
X-API-Secret: your_secret
Content-Type: application/json

Get API Keys

Follow these steps to obtain your API credentials:

Endpoints

Health Check

Health check endpoint to verify the QR & Barcode service status and available generation backends.

Response

{
  "success": true,
  "status": "healthy",
  "api_hub_backend": true,
  "segno": true,
  "python_barcode": true,
  "zipfile": true,
  "csp_protection": true
}

Code Examples

import requests

url = "https://api.chemhub.com/api/v1/qr/health"

headers = {
    "X-API-Key": "your_api_key",
    "X-API-Secret": "your_secret"
}

res = requests.get(url, headers=headers)
print(res.json())

curl -X GET https://api.chemhub.com/api/v1/qr/health \
-H "X-API-Key: your_api_key" \
-H "X-API-Secret: your_secret"

fetch('https://api.chemhub.com/api/v1/qr/health', {
  method: 'GET',
  headers: {
    'X-API-Key': 'your_api_key',
    'X-API-Secret': 'your_secret'
  }
})
.then(res => res.json())
.then(console.log);

Generate QR Code or Barcode

Generate a QR code or linear barcode. Send the request as JSON with Content-Type: application/json.

JSON Parameters

cURL Example

curl -X POST "https://api.chemhub.com/api/v1/qr/generate" \
  -H "X-API-Key: your_api_key" \
  -H "X-API-Secret: your_secret" \
  -H "Content-Type: application/json" \
  -d '{
    "type": "qrcode",
    "data": "https://chemhub.com",
    "output": "png",
    "scale": 10,
    "eclevel": "M"
  }' \
  --output qr.png

Code Examples

import requests

url = "https://api.chemhub.com/api/v1/qr/generate"

headers = {
    "X-API-Key": "your_api_key",
    "X-API-Secret": "your_secret",
    "Content-Type": "application/json"
}

payload = {
    "type": "qrcode",
    "data": "https://chemhub.com",
    "output": "png",
    "scale": 10,
    "border": 4,
    "eclevel": "M",
    "dark": "#000000"
}

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

if response.status_code == 200:
    with open("qr.png", "wb") as out:
        out.write(response.content)
    print("QR code saved to qr.png")
else:
    print(response.json())

const payload = {
  type: 'qrcode',
  data: 'https://chemhub.com',
  output: 'png',
  scale: 10,
  eclevel: 'M'
};

fetch('https://api.chemhub.com/api/v1/qr/generate', {
  method: 'POST',
  headers: {
    'X-API-Key': 'your_api_key',
    'X-API-Secret': 'your_secret',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify(payload)
})
.then(async res => {
  if (res.ok) {
    const blob = await res.blob();
    const url = URL.createObjectURL(blob);
    console.log('QR code URL:', url);
  } else {
    console.log(await res.json());
  }
});

Batch Generate

Generate up to 50 QR codes or barcodes in a single request. Each item in the items array is generated independently and the results are returned as a ZIP archive (qr_barcode_batch.zip).

JSON Parameters

Item Fields

Each item supports the same fields as POST /qr/generate, plus an optional filename for the archive entry.

cURL Example

curl -X POST "https://api.chemhub.com/api/v1/qr/generate/batch" \
  -H "X-API-Key: your_api_key" \
  -H "X-API-Secret: your_secret" \
  -H "Content-Type: application/json" \
  -d '{
    "items": [
      {"type": "qrcode", "data": "https://chemhub.com", "filename": "home.png"},
      {"type": "code128", "data": "ABC-12345", "filename": "sku.png"}
    ]
  }' \
  --output batch.zip

Code Examples

import requests

url = "https://api.chemhub.com/api/v1/qr/generate/batch"

headers = {
    "X-API-Key": "your_api_key",
    "X-API-Secret": "your_secret",
    "Content-Type": "application/json"
}

payload = {
    "items": [
        {"type": "qrcode", "data": "https://chemhub.com", "filename": "home.png"},
        {"type": "code128", "data": "ABC-12345", "filename": "sku.png"}
    ]
}

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

if response.status_code == 200:
    with open("batch.zip", "wb") as out:
        out.write(response.content)
    print("Batch saved to batch.zip")
else:
    print(response.json())

const payload = {
  items: [
    { type: 'qrcode', data: 'https://chemhub.com', filename: 'home.png' },
    { type: 'code128', data: 'ABC-12345', filename: 'sku.png' }
  ]
};

fetch('https://api.chemhub.com/api/v1/qr/generate/batch', {
  method: 'POST',
  headers: {
    'X-API-Key': 'your_api_key',
    'X-API-Secret': 'your_secret',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify(payload)
})
.then(async res => {
  if (res.ok) {
    const blob = await res.blob();
    const url = URL.createObjectURL(blob);
    console.log('Batch ZIP URL:', url);
  } else {
    console.log(await res.json());
  }
});

Python SDK

Complete Python SDK covering health check, single-code generation, and batch generation.

import requests
import io

BASE_URL = "https://api.chemhub.com/api/v1"
API_KEY = "YOUR_API_KEY"
API_SECRET = "YOUR_API_SECRET"

headers = {
    "X-API-Key": API_KEY,
    "X-API-Secret": API_SECRET
}

# --- Health Check ---
def check_health():
    return requests.get(f"{BASE_URL}/qr/health", headers=headers).json()

# --- Generate a single QR code or barcode ---
def generate_code(code_type="qrcode", data="https://chemhub.com",
                  output="png", output_path="code.png", **options):
    payload = {"type": code_type, "data": data, "output": output}
    payload.update(options)
    response = requests.post(
        f"{BASE_URL}/qr/generate",
        headers=headers,
        json=payload
    )

    if response.status_code == 200:
        if output == "base64":
            result = response.json()
            print("Encoded base64 data:", result.get("base64")[:64], "...")
            return result
        with open(output_path, "wb") as out:
            out.write(response.content)
        print(f"Saved: {output_path}")
        return output_path
    print(f"Error: {response.status_code} - {response.text}")
    return None

# --- Generate a batch of codes (returns a ZIP) ---
def generate_batch(items, output_path="batch.zip"):
    response = requests.post(
        f"{BASE_URL}/qr/generate/batch",
        headers=headers,
        json={"items": items}
    )
    if response.status_code == 200:
        with open(output_path, "wb") as out:
            out.write(response.content)
        print(f"Saved: {output_path}")
        return output_path
    print(f"Error: {response.status_code} - {response.text}")
    return None

# --- Test all endpoints ---
if __name__ == "__main__":
    print("=== QR & BARCODE API TEST ===")

    health = check_health()
    print(f"Health: {health.get('status', 'unknown')}")
    print(f"Segno: {health.get('segno')} | python-barcode: {health.get('python_barcode')}")

    print("\n1. Generating QR code:")
    generate_code(
        code_type="qrcode",
        data="https://chemhub.com",
        output="png",
        output_path="qr.png",
        scale=10,
        eclevel="M"
    )

    print("\n2. Generating Code 128 barcode:")
    generate_code(
        code_type="code128",
        data="ABC-12345",
        output="svg",
        output_path="barcode.svg"
    )

    print("\n3. Batch generation:")
    generate_batch([
        {"type": "qrcode", "data": "https://chemhub.com", "filename": "home.png"},
        {"type": "ean13", "data": "5901234123457", "filename": "sku.png"}
    ])

Errors & Status Codes

Error Response Format

{
  "success": false,
  "error": "Invalid code type",
  "message": "Supported types: qrcode, code128, ean13, upca, ean8, itf, itf14, code39"
}

Status Codes

Limitations