Fix ACF JSON Sync Not Working (Full Guide + Best Practices 2025)

ACF JSON sync is powerful for managing custom fields in development environments, but it can break during migrations, updates, or theme changes. If your JSON sync is missing, greyed out, or changes don’t apply, this guide walks you through real-world fixes.

Why ACF JSON Sync Breaks

Common triggers:

• Fields not showing in sync tab
• Sync button missing after migration
• Fields revert after saving
• JSON folder ignored by ACF
• UI changes not reflected in templates
• Theme switched or using child theme
• Permissions or version mismatch

Quick Fix Checklist

Run through these first:

• Folder exists: /acf-json/
• Folder writable (775 recommended)
• Same ACF version across environments
• Save field group once manually
• Clear WordPress cache / OPcache
• Remove old JSON files and refresh ACF field groups page

chmod -R 775 wp-content/themes/your-theme/acf-json

ACF JSON Path Setup

Confirm the save + load locations. Add to your theme/plugin:

// Save JSON
add_filter('acf/settings/save_json', function ($path) {
  return get_stylesheet_directory() . '/acf-json';
});

// Load JSON
add_filter('acf/settings/load_json', function ($paths) {
  unset($paths[0]);
  $paths[] = get_stylesheet_directory() . '/acf-json';
  return $paths;
});

If using a child theme

return get_stylesheet_directory() . '/acf-json'; // child theme
// instead of get_template_directory()

Full Fix Workflow

Recommended process for clean sync:

1. Backup JSON folder
2. Delete stale .json files
3. Commit fresh JSON to Git repo (if using Git)
4. Open ACF → Field Groups
5. Click Sync available fields
6. Re-save each field group once
7. Clear cache + refresh pages with ACF data

Verification snippet:

var_dump(get_stylesheet_directory() . '/acf-json');

If it prints expected path, the theme is pointing correctly.

Environment Version Fix

Always match versions:

Mismatched ACF versions cause sync issues.

Best Practices

• One source of truth (dev)
• JSON folder in Git (always commit changes)
• Avoid editing fields in production
• Always "Save Field Group" after deploy
• Keep folder name exactly acf-json

Elementor / Bricks Builder Note

After syncing:

• Elementor: Regenerate CSS + Data → Clear cache
• Bricks: Rebuild Cache
• Block Editor: Clear WP transient cache

Common Issues Table

Example Folder Structure

wp-content/
  themes/
    your-theme/
      acf-json/
        group_header.json
        group_footer.json
        group_home.json

Testing Snippet

echo get_field('hero_title') ?: 'ACF field empty – check sync';

ACF JSON Sync Checklist

• acf-json folder exists in theme
• Permissions set (775)
• Correct save_json and load_json
• Same ACF version everywhere
• Field groups synced + re-saved
• Caches cleared (WP + server)
• Only one JSON sync location

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