Category: Dev Tips & Snippets

Using AJAX in your plugin can make it feel fast and modern — but if you don’t structure it right, it can become messy and insecure fast.

Here’s how I handle AJAX calls the clean and secure way in WordPress.

1. Enqueue Your Script with ajaxurl

When enqueuing your JavaScript, always localize it with the ajaxurl.

add_action( 'admin_enqueue_scripts', function() {
    wp_enqueue_script( 'my-plugin-admin', plugin_dir_url( __FILE__ ) . 'admin.js', [ 'jquery' ], '1.0', true );
    
    wp_localize_script( 'my-plugin-admin', 'myPlugin', [
        'ajax_url' => admin_url( 'admin-ajax.php' ),
        'nonce'    => wp_create_nonce( 'my_plugin_nonce' ),
    ] );
});

2. The JS Side (Calling AJAX)

jQuery(document).ready(function($) {
    $('#my-button').on('click', function() {
        $.post(myPlugin.ajax_url, {
            action: 'my_plugin_do_something',
            nonce: myPlugin.nonce,
            data: 'SomeValue'
        }, function(response) {
            console.log('Server says:', response);
        });
    });
});

3. The PHP Side (Handling AJAX)

add_action( 'wp_ajax_my_plugin_do_something', 'my_plugin_do_something_callback' );

function my_plugin_do_something_callback() {
    check_ajax_referer( 'my_plugin_nonce', 'nonce' );

    // Capability check if needed
    if ( ! current_user_can( 'manage_options' ) ) {
        wp_send_json_error( 'Not allowed' );
    }

    $value = sanitize_text_field( $_POST['data'] ?? '' );

    // Do something here...

    wp_send_json_success( 'Success! You sent: ' . $value );
}

Bonus: For Frontend Users

If you want AJAX support on the frontend too:

add_action( 'wp_ajax_nopriv_my_plugin_do_something', 'my_plugin_do_something_callback' );

This lets non-logged-in users run the same AJAX handler — great for forms, voting, tracking, etc.

Final Thought

Keep your AJAX code:

• Localized with nonces
• Protected with check_ajax_referer()
• Cleanly separated in JS and PHP
• Always sanitized and validated

Done right, it makes your plugins feel snappy and pro.

Security isn’t the flashiest part of plugin development — but it’s the part that breaks trust the fastest when ignored.

These are the basics I always keep in mind while building plugins. They’re simple, but missing even one of them can open up real problems.

1. Escape Output, Always

Whenever I print something to the screen, especially user-generated content or dynamic settings, I escape it properly:

echo esc_html( $setting_value );

Use the right escaping function for the context:

• esc_html() for regular text
• esc_attr() for input values
• esc_url() for links
• wp_kses_post() if allowing some HTML

If you forget this, it opens doors to XSS attacks.

2. Sanitize Input Before Saving

Before saving anything to the database — whether it’s from a form or a setting screen — I sanitize it.

$sanitized = sanitize_text_field( $_POST['your_field'] );

Other useful sanitizers:

• sanitize_email()
• sanitize_textarea_field()
• absint()
• esc_url_raw()

Even if it “looks safe,” I sanitize it anyway.

3. Always Use Nonces for Forms & AJAX

A nonce protects your forms and AJAX requests from being abused by external scripts or bad actors.

For forms:

wp_nonce_field( 'my_plugin_action', 'my_plugin_nonce' );

On submit:

if ( ! isset( $_POST['my_plugin_nonce'] ) || 
     ! wp_verify_nonce( $_POST['my_plugin_nonce'], 'my_plugin_action' ) ) {
    return; // Invalid request
}

For AJAX: Same logic applies — pass and verify a nonce.

4. Capability Checks Matter

Before saving data or doing anything admin-related, I make sure the current user has permission to do so.

if ( ! current_user_can( 'manage_options' ) ) {
    return;
}

I don’t rely only on menu access. I protect everything behind capability checks too.

5. Never Trust $_POST or $_GET Blindly

I treat all global inputs ($_POST, $_GET, $_REQUEST, etc.) as untrusted by default.
Even if it’s a simple text field, I treat it with caution.

Trust your logic, not the input.

Final Thought

You don’t need to be a security expert to write secure plugins.
Just follow these simple habits every time, and you’ll avoid 90% of common issues.

It’s not about fear — it’s about respect.
For your users, their data, and the trust they place in your work.

Sometimes your plugin or theme needs to show a message in the WordPress admin area — maybe a success message after saving settings, or a warning if something is missing.

Here’s how I usually do it:
Keep it simple, clean, and native.

The Snippet

add_action( 'admin_notices', function() {
    if ( ! current_user_can( 'manage_options' ) ) {
        return;
    }

    echo '<div class="notice notice-success is-dismissible">';
    echo '<p>Your custom admin notice goes here.</p>';
    echo '</div>';
});

How It Works

• Hooks into admin_notices, which is used by WordPress to display messages at the top of admin screens.
• notice-success gives it a green success style. You can also use:
  • notice-error (red)
  • notice-warning (yellow)
  • notice-info (blue)
• is-dismissible makes it closable.
• Always wrap with a capability check like manage_options to avoid showing notices to users who don’t need to see them.

Bonus: Show it only on specific pages

You can limit where the notice appears like this:

if ( get_current_screen()->id === 'settings_page_my-plugin' ) {
    // show notice
}

I use this pattern in almost every plugin I write.
Clean admin messages go a long way in making your tools feel more polished and professional.