Disable Field Validation in ACF Blocks

Last updated Jun 10, 2024


Field validation is enabled by default for all ACF Blocks. Existing posts with ACF Blocks are validated the next time the post is edited. If any fields fail validation, the post cannot be saved until those issues are resolved. In some cases, you may wish to disable field validation for a particular ACF Block. This doc shows how to disable field validation by adding the validate: false attribute to the ACF key section of the block.json file.

Validation for fields contained in ACF Blocks was introduced in ACF PRO 6.3. The fields in ACF Blocks can have any of the same validation rules applied to them as any custom field, such as being required, minimum and maximum values, and so on. This works the same way as validation for field groups assigned to posts, pages, or other data objects.


The validation attribute for ACF Blocks defaults to true, so you will have to make adjustments to the block.json file to prevent this behavior for an individual block. The validate: false attribute is added to the ACF key section of your block.json file:

    "name": "acf/testimonial",
    "title": "Testimonial",
    "description": "A custom testimonial block that uses ACF fields.",
    "style": [ "file:./testimonial.css" ],
    "category": "formatting",
    "icon": "admin-comments",
    "keywords": ["testimonial", "quote"],
    "acf": {
        "mode": "preview",
        "renderTemplate": "testimonial.php",
        "validate": false
    "supports": {
        "anchor": true