Security should never be an afterthought when building WordPress plugins. A vulnerable plugin can compromise an entire website. Here are the top 10 security best practices every developer should follow:
1. Sanitize and Escape User Input
Always use functions like sanitize_text_field(), esc_html(), and esc_attr() to clean data before saving or outputting it.
2. Use Nonces for Form Security
Protect against Cross-Site Request Forgery (CSRF) attacks by adding WordPress nonces (wp_nonce_field()) to all forms.
3. Validate Data on Both Client and Server
Client-side checks improve UX, but server-side validation is essential for real security.
4. Limit User Capabilities
Use current_user_can() to ensure only authorized users can access certain features.
5. Avoid Direct File Access
Start PHP files with if ( !defined('ABSPATH') ) exit; to prevent direct script execution.
6. Keep Dependencies Updated
Outdated libraries can be exploited. Always keep dependencies up to date.
7. Escape Output
Never print raw user input — always escape output using WordPress escaping functions.
8. Use Prepared Statements
When interacting with the database, use $wpdb->prepare() to prevent SQL injection.
9. Protect Sensitive Data
Never store API keys or passwords in plain text; use wp-config.php or environment variables.
10. Test for Vulnerabilities
Use tools like WPScan or PHPStan to catch potential security flaws before release.
By following these practices, your plugins will remain secure, trustworthy, and future-proof.
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