WordPress Forms and Validation

WordPress Forms and Validation — a practical guide to WordPress form validation with clear examples you can reuse in real projects.

WordPress Plugin Development Series (49/95). Prefer one article? Read the complete WordPress plugin development tutorial.

Short description

Never trust client-only validation. Return clear field errors and preserve safe old input.

Validation pattern

$errors = [];
if ($email === '' || ! is_email($email)) {
    $errors['email'] = 'Enter a valid email';
}
if ($errors) {
    // show errors
}