1. Check the dependencies
Install and activate Advanced Custom Fields first. Either ACF Free or ACF Pro can be used with either Validated Field edition. Licensed ACF input types still require ACF Pro.
Requirements: WordPress 6.0 or newer, PHP 8.0 or newer, and ACF 6.0 or newer.
2. Install Free
Install the Free plugin package in WordPress and activate it. The plugin directory is validated-field-for-acf; its main file is validated_field.php. The WordPress plugin listing uses the existing name Validated Field.
3. Add a validated input
Open an ACF field group and add a field of type Validated Field. Choose the underlying native input type, such as a text field. Configure a validation rule and a useful message for editors.
For a product SKU such as VLD-2026, use this regular expression, including its PHP delimiters:
/^[A-Z]{3}-[0-9]{4}$/A suitable message is Use three uppercase letters, a dash and four digits. Test a valid value and an invalid value before applying the field group to real content.
4. Decide what must be unique
If the SKU identifies a product, choose the uniqueness scope that matches the model. A post-type scope checks against other posts in that type. A narrower key scope changes which fields are compared. Read the validation guide before relying on the chosen scope.
5. Add Pro when you need its tools
Pro is a separate add-on installed beside Free, with directory validated-field-pro and main file validated-field-pro.php. It depends on a compatible Free version. It adds formulas, rollups, automation and advanced authoring; it does not replace Free or include ACF.