Custom Validation Rules in CodeIgniter

Custom Validation Rules in CodeIgniter — a practical guide to CodeIgniter custom validation with clear examples you can reuse in real projects.

CodeIgniter Tutorial Series (25/74). Prefer one article? Read the complete CodeIgniter tutorial.

Short description

Add reusable custom rules when you need project-specific validation (unique formats, domain checks, etc.).

Custom rule callback style

$rules = [
    'username' => [
        'rules'  => 'required|min_length[3]',
        'errors' => ['required' => 'Username is required'],
    ],
];
// Or register custom rules in ConfigValidation / rule classes.