🔧 REST API Documentation

Generate Codes Programmatically via API

A single HTTP GET call — integrate QR & barcode generation directly into Excel, Google Sheets, any ERP system or custom application. All you need is your API key and your data.

🚀 Quick Start

GET https://ultdtc.com/api?api_key=YOUR_KEY&data=Hello+World&type=qr&transparent=1&output=image

Response: transparent PNG image stream — use directly in <img src="...">, save to disk, or embed in Excel.

🔑 Authentication

Add api_key to every request. Get your key from the Dashboard under Developer API (requires Unlimited plan).

📋 Parameters

Parameter	Default	Description
`api_key` *	required	Your secret API key — required in every request.
`data` *	required	The URL, text, or barcode value to encode.
`type`	qr	`qr` or `barcode`
`color`	000000	Foreground HEX color without # (e.g. 1a1aff)
`transparent`	1	`1` = transparent background (default), `0` = solid
`bg_color`	ffffff	Background HEX color — only used when transparent=0
`width`	qr:10 / bc:2	QR: module size in px (2–40) · Barcode: bar-unit width (1–8)
`height`	80	Barcode height in px (20–400). Ignored for QR.
`output`	json	`image` = direct PNG stream · `json` = JSON with base64

💻 Integration Examples

cURL / Terminal

# Download a transparent QR code

curl "https://ultdtc.com/api?api_key=YOUR_KEY&data=Hello+World&type=qr&transparent=1&output=image" \
-o qrcode.png

PHP

<?php
$url = "https://ultdtc.com/api?" . http_build_query([
    "api_key"     => "YOUR_KEY",
    "data"        => "https://example.com",
    "type"        => "qr",
    "transparent" => 1,
    "output"      => "image",
]);
file_put_contents("qrcode.png", file_get_contents($url));
?>

Python (requests)

import requests

resp = requests.get("https://ultdtc.com/api", params={
    "api_key":     "YOUR_KEY",
    "data":        "https://example.com",
    "type":        "qr",
    "transparent": 1,
    "output":      "image",
})
with open("qrcode.png", "wb") as f:
    f.write(resp.content)
print("Done!")

JavaScript (fetch)

// Get base64 PNG via JSON output
const params = new URLSearchParams({
  api_key: "YOUR_KEY",
  data:    "https://example.com",
  type:    "qr",
  transparent: 1,
  output: "json"
});

const res  = await fetch("https://ultdtc.com/api?" + params);
const json = await res.json();
document.getElementById("qr-img").src = json.image_base64;

📊 Excel Integration — Auto-Generate Barcodes & QR Codes

You can auto-generate thousands of QR codes or barcodes directly from Excel in two steps: put your data in column A, call the API with each value.

Step 1: Sheet Layout

A	B	C
Data / URL	API URL	Image (=IMAGE)
https://example.com	=CONCAT("https://ultdtc.com/api?api_key=KEY&data=",ENCODEURL(A2),"&type=qr&transparent=1&output=image")	=IMAGE(B2)
Product-SKU-1234	=CONCAT("https://ultdtc.com/api?api_key=KEY&data=",ENCODEURL(A3),"&type=barcode&output=image")	=IMAGE(B3)

* =IMAGE() is available in Excel 365 and Google Sheets. In Google Sheets: =IMAGE(B2)

Step 2: VBA Macro to Auto-Download Images

Open the VBA editor (Alt+F11), create a new module, and paste this code:

Sub GenerateQRCodes()
    Dim ws As Worksheet
    Dim apiKey As String
    Dim baseUrl As String
    Dim lastRow As Long
    Dim i As Long
    Dim qrUrl As String
    Dim savePath As String

    apiKey  = "YOUR_API_KEY_HERE"
    baseUrl = "https://ultdtc.com/api"
    ws      = ActiveSheet
    lastRow = ws.Cells(ws.Rows.Count, "A").End(xlUp).Row
    savePath = ThisWorkbook.Path & "\qr_codes\"

    ' Create folder if it does not exist
    If Dir(savePath, vbDirectory) = "" Then MkDir savePath

    For i = 2 To lastRow
        Dim data As String
        data = ws.Cells(i, 1).Value
        If Trim(data) = "" Then GoTo NextRow

        qrUrl = baseUrl & "?api_key=" & apiKey _
              & "&data=" & WorksheetFunction.EncodeURL(data) _
              & "&type=qr&transparent=1&output=image"

        Dim xhr As Object
        Set xhr = CreateObject("MSXML2.XMLHTTP")
        xhr.Open "GET", qrUrl, False
        xhr.send

        Dim fileName As String
        fileName = savePath & "qr_" & i & ".png"

        Dim stream As Object
        Set stream = CreateObject("ADODB.Stream")
        stream.Type = 1  ' Binary
        stream.Open
        stream.Write xhr.responseBody
        stream.SaveToFile fileName, 2
        stream.Close

        ws.Cells(i, 3).Value = fileName   ' Store path in col C
        NextRow:
    Next i

    MsgBox "Done! " & (lastRow - 1) & " QR codes saved to " & savePath
End Sub

📦 JSON Response (output=json)

{
  "success": true,
  "type": "qr",
  "transparent": true,
  "caller_ip": "203.0.113.5",
  "image_base64": "data:image/png;base64,iVBORw0KGgo...",
  "daily_requests_remaining": 87
}

When daily_requests_remaining reaches 0, the API returns HTTP 429.

🔒 IP Allowlist

From your Dashboard you can restrict your API key to specific IP addresses (e.g. your server or office network). If no IPs are added, all IPs are accepted. Manage IPs →