How to Generate QR Codes via the REST API

If you’re running automated marketing campaigns or need to programmatically create QR codes as part of a workflow — for example, generating a unique QR code for each Mailchimp subscriber — Qyrr’s REST API endpoint allows you to do exactly that: create a QR code post and generate the PNG image file entirely server-side, then get back a direct URL to use anywhere.

In this guide, we’ll walk through how to enable the feature, set up authentication, and make requests using PHP.

Table of Contents

Step 1: Enable the REST API

The REST API endpoint is disabled by default. To turn it on:

Go to Qyrr > Settings from your WordPress dashboard.
Find the REST API card and toggle Enable REST API on.
Click Save Settings.

Once saved, the endpoint URL will appear below the toggle. You can copy it directly with the Copy button.

Step 2: Create a WordPress Application Password

The endpoint uses WordPress Application Passwords for authentication — a built-in WordPress feature (since WP 5.6) that lets you generate per-app credentials without exposing your main account password.

Go to Users > Profile (or click the link in the REST API card in Settings).
Scroll down to the Application Passwords section.
Enter a name for your app and click Add New Application Password.
Copy the generated password immediately — it will only be shown once.

You’ll need two things for authentication: your WordPress username and the Application Password you just generated.

Step 3: Make a request from PHP

The endpoint accepts a POST request with a JSON body. The simplest way to call it from PHP (e.g. from functions.php, a plugin, or a custom script) is using WordPress’s built-in wp_remote_post().

Basic example — URL QR code

$username = 'your_wp_username';
$app_password = 'xxxx xxxx xxxx xxxx xxxx xxxx'; // Application Password from your profile

$response = wp_remote_post(
    'https://your-site.com/wp-json/qyrr/v1/generate',
    [
        'headers' => [
            'Authorization' => 'Basic ' . base64_encode( $username . ':' . $app_password ),
            'Content-Type'  => 'application/json',
        ],
        'body' => wp_json_encode( [
            'title'                => 'My QR Code',
            'source'               => 'url',
            'url'                  => 'https://example.com',
            'size'                 => 400,
            'fill-color'           => '#000000',
            'background-color'     => '#ffffff',
            'error-handling-level' => 'H',
        ] ),
        'timeout' => 30,
    ]
);

if ( is_wp_error( $response ) ) {
    error_log( 'QR generation failed: ' . $response->get_error_message() );
    return;
}

$body = json_decode( wp_remote_retrieve_body( $response ), true );

$post_id   = $body['post_id'];   // WordPress post ID of the new QR code
$image_url = $body['image_url']; // Direct URL to the generated PNG file

The response always contains two fields: post_id (the ID of the created QR code post in WordPress) and image_url (a direct, publicly accessible URL to the generated PNG image).

Email QR code

$body = wp_json_encode( [
    'title'  => 'Contact Email',
    'source' => 'email',
    'email'  => '[email protected]',
    'size'   => 400,
] );

Phone / WhatsApp QR code

// Phone
$body = wp_json_encode( [
    'title'  => 'Call us',
    'source' => 'phone',
    'phone'  => '+40721000000',
    'size'   => 400,
] );

// WhatsApp (phone without + or spaces)
$body = wp_json_encode( [
    'title'          => 'WhatsApp Support',
    'source'         => 'whatsapp',
    'phone'          => '40721000000',
    'whatsapp-text'  => 'Hello! I have a question.',
    'size'           => 400,
    'fill-color'     => '#25D366',
] );

SMS QR code

$body = wp_json_encode( [
    'title'    => 'SMS Promo',
    'source'   => 'sms',
    'phone'    => '+40721000000',
    'sms-text' => 'Hi! Here is your promo code: SAVE20',
    'size'     => 400,
] );

Free text QR code (Wi-Fi, vCard, etc.)

// Wi-Fi
$body = wp_json_encode( [
    'title'  => 'Office WiFi',
    'source' => 'text',
    'text'   => 'WIFI:T:WPA;S:NetworkName;P:Password123;;',
    'size'   => 400,
] );

// vCard contact
$vcard = implode( "\n", [
    'BEGIN:VCARD',
    'VERSION:3.0',
    'FN:John Doe',
    'TEL:+40721000000',
    'EMAIL:[email protected]',
    'END:VCARD',
] );

$body = wp_json_encode( [
    'title'  => 'John Doe Contact',
    'source' => 'text',
    'text'   => $vcard,
    'size'   => 500,
    'error-handling-level' => 'M',
] );

QR code with logo

You can overlay a logo on the QR code by passing the URL of an image already uploaded to your WordPress media library. Make sure to use error correction level H when adding a logo — this ensures the QR code remains scannable even with part of it covered.

$body = wp_json_encode( [
    'title'                => 'Branded QR Code',
    'source'               => 'url',
    'url'                  => 'https://example.com',
    'size'                 => 500,
    'fill-color'           => '#000000',
    'background-color'     => '#ffffff',
    'error-handling-level' => 'H',
    'logo-upload'          => 'https://your-site.com/wp-content/uploads/logo.png',
    'logo-size'            => 25, // percentage of QR size (5–50)
] );

QR code with label text

$body = wp_json_encode( [
    'title'       => 'Scan me QR',
    'source'      => 'url',
    'url'         => 'https://example.com',
    'size'        => 400,
    'label-text'  => 'Scan to visit our website',
    'font-color'  => '#333333',
    'quiet-zone'  => 3,
] );

All available parameters

Parameter	Type	Default	Description
`title`	string	QR Code	Name of the QR code post in WordPress
`source`	string	required	`url`, `email`, `phone`, `sms`, `whatsapp`, `text`, `post`
`url`	string	—	Required when `source` is `url`
`email`	string	—	Required when `source` is `email`
`phone`	string	—	Required when `source` is `phone`, `sms`, or `whatsapp`
`sms-text`	string	—	Optional message body for SMS
`whatsapp-text`	string	—	Optional pre-filled message for WhatsApp
`text`	string	—	Required when `source` is `text`
`size`	integer	400	Image size in pixels (minimum 100)
`fill-color`	hex string	`#000000`	Color of the QR code modules
`background-color`	hex string	`#ffffff`	Background color
`error-handling-level`	L / M / Q / H	H	Error correction level — use H when adding a logo
`quiet-zone`	integer 0–10	0	White border around the QR code
`logo-upload`	URL	—	URL of an image from your own media library
`logo-size`	integer 5–50	30	Logo size as a percentage of the QR code size
`label-text`	string	—	Text displayed below the QR code
`font-color`	hex string	`#000000`	Color of the label text

Using the image URL in Mailchimp

The image_url returned in the response is a permanent, publicly accessible link to the generated PNG file. You can use it directly in any system that accepts an image URL.

A common workflow with Mailchimp looks like this:

Use a Mailchimp webhook or a tool like Make (formerly Integromat) or Zapier to trigger a PHP script when a new subscriber is added.
The script calls the Qyrr REST endpoint with the subscriber’s data (e.g. their unique URL or email) and receives back an image_url.
That URL is then passed to the Mailchimp API to populate a merge tag or update the subscriber’s profile data.
The email template uses that merge tag to display the personalized QR code image inline.

// Example: generate a QR code per subscriber and store the URL
function generate_qr_for_subscriber( string $subscriber_url, string $subscriber_name ): string {
    $username     = 'your_wp_username';
    $app_password = 'xxxx xxxx xxxx xxxx xxxx xxxx';

    $response = wp_remote_post(
        'https://your-site.com/wp-json/qyrr/v1/generate',
        [
            'headers' => [
                'Authorization' => 'Basic ' . base64_encode( $username . ':' . $app_password ),
                'Content-Type'  => 'application/json',
            ],
            'body' => wp_json_encode( [
                'title'                => 'QR — ' . $subscriber_name,
                'source'               => 'url',
                'url'                  => $subscriber_url,
                'size'                 => 400,
                'error-handling-level' => 'H',
            ] ),
            'timeout' => 30,
        ]
    );

    if ( is_wp_error( $response ) ) {
        return '';
    }

    $body = json_decode( wp_remote_retrieve_body( $response ), true );

    return $body['image_url'] ?? '';
}

// Usage
$qr_url = generate_qr_for_subscriber( 'https://example.com/?ref=john', 'John Doe' );
// $qr_url is now ready to pass to Mailchimp or any email platform

Need help with a specific integration? Check the full Qyrr documentation or reach out via support.