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 textesc_attr()
for input valuesesc_url()
for linkswp_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.
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