Security Best Practices

Input Validation

Data Sanitization Functions

Output Escaping

esc_html() Function

esc_attr() Function

esc_url() Function

wp_kses() Function

Creating Nonces

Verifying Nonces

Nonce Security

SQL Injection Prevention

Cross-Site Scripting Prevention

Cross-Site Request Forgery Prevention

File Upload Security

Directory Permissions

Preventing Direct File Access