A developer’s life beyond the screen.

7. Security and Performance Essentials

Security and performance are two areas beginners often ignore, but they are extremely important in real-world WordPress development.
Even a small mistake can create vulnerabilities, slow down the website, or break important features.

This article explains the essential things you should follow from day one.

Understanding Security in WordPress

When working with user input, database queries, forms, or URLs, you must always assume that data can be unsafe.
Security in WordPress mainly revolves around three concepts:

  • Sanitizing
  • Escaping
  • Using nonces

Let’s go through them simply.

Sanitizing Data

Sanitizing means cleaning the data before saving it.

Example:

$name = sanitize_text_field($_POST['name']);

This removes harmful characters so it’s safe to save in the database.

Common sanitizing functions:

  • sanitize_text_field()
  • sanitize_email()
  • sanitize_url()
  • intval()
  • sanitize_key()

Always sanitize anything coming from forms, API requests, or custom fields.

Escaping Output

Escaping means cleaning the data before displaying it on a page.

Example:

echo esc_html($name);

This prevents unwanted HTML or scripts from being printed.

Common escaping functions:

  • esc_html()
  • esc_attr()
  • esc_url()
  • esc_textarea()

A simple rule:
Sanitize when saving, escape when outputting.

Using Nonces (Important for Forms)

A nonce is a security token that protects your code from unwanted requests (CSRF attacks).

When creating a form in admin:

wp_nonce_field('my_action', 'my_nonce');

Then verify it:

check_admin_referer('my_action', 'my_nonce');

If the nonce is missing or invalid, WordPress will block the request.
This keeps your forms safe.

Working with the Database Safely

Never write raw SQL without precautions.
If you use $wpdb, always prepare statements:

$wpdb->get_results(
    $wpdb->prepare("SELECT * FROM $wpdb->posts WHERE post_type = %s", $type)
);

Never insert user data directly into queries.
Prepared statements prevent SQL injection attacks.

Performance Basics for Beginners

Performance is not only about speed — it’s about not overloading WordPress with unnecessary work.

Here are the simple habits you should follow.

Load Scripts the Right Way

Never hard-code scripts with <script> tags.
Always use:

wp_enqueue_script();
wp_enqueue_style();

Also, load scripts only where needed, not on every page.

Avoid Heavy Operations on Every Request

Some beginners make mistakes like:

  • Running complex database queries on each page load
  • Loading large files unnecessarily
  • Using wp_remote_get() inside loops
  • Doing expensive operations inside the init hook

Be mindful of what your plugin does.

Use Caching When Possible

For data that doesn’t change often, use:

set_transient();
get_transient();
delete_transient();

Caching reduces database load and speeds up the page.

Optimize Database Use

  • Don’t store large chunks of data in wp_options
  • Avoid storing unnecessary values in postmeta
  • Clean up data on plugin uninstall if possible

A clean database keeps WordPress fast.

Use Smaller, Efficient Files

  • Minify CSS and JS
  • Combine assets when possible
  • Avoid loading unnecessary libraries

Small optimizations add up on large websites.

Why These Essentials Matter

Many beginners focus only on features, not on safety or speed.
But in real-world environments:

  • Security keeps your site safe from hackers
  • Performance keeps your site fast and prevents server crashes
  • Clean code prevents errors and makes maintenance easier

Following these simple rules will make your plugins and themes more professional and reliable.

What’s Next

In the final article of this course, we’ll cover Packaging and Releasing Your Plugin, where you’ll learn:

  • How to prepare a plugin for public release
  • How to write a proper readme
  • How to structure your assets
  • How to version your plugin
  • How to publish using GitHub or WordPress.org