Advanced Custom Fields (ACF): Free vs Pro & Setup (2026)
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Advanced Custom Fields (ACF) is the plugin that transforms WordPress from a blogging platform into a genuine content management system. Powering over 3 million websites, it gives developers and site builders a drag-and-drop field builder to attach structured data to any post, page, user, taxonomy term, or media item — no code required.
If your site needs more than a title and body text — product specs, event details, team bios, property listings, course data — ACF is almost certainly the right tool. It ships free with over 30 field types, and its Pro tier adds the fields that make complex content architectures possible.
This guide covers what ACF is, every major field type, how the free and Pro tiers compare, how ACF pairs with custom post types, and how AI assistants can now read and write ACF field data through a WordPress MCP server.
What Is Advanced Custom Fields?
Advanced Custom Fields is a WordPress plugin created by Elliot Condon, now owned and maintained by WP Engine. It lets you define field groups — collections of typed input fields — and attach them to any area of your WordPress site using location rules.
The result: structured, typed data stored alongside your content, accessible via ACF’s template functions (get_field(), the_field()) or the WordPress REST API.
ACF handles both sides of the problem:
- Content modeling — define the fields that describe your content (a “Property” post needs a price, bedrooms, bathrooms, square footage)
- Editorial UI — those fields appear automatically in the WordPress post editor for the content types you specify
As of version 6.1, ACF also lets you register custom post types and taxonomies directly from its UI — no separate plugin or hand-written register_post_type() code needed.
ACF Field Types
The free version of ACF ships with over 30 field types. They fall into a few natural groups:
Text & Content
- Text — single-line text input
- Textarea — multi-line text
- Number — numeric input with min/max/step
- Range — slider input
- Email — validated email address
- URL — validated URL
- Password — masked text input
- WYSIWYG — full TinyMCE rich-text editor
- oEmbed — embed URLs (YouTube, Vimeo, Twitter, etc.)
Choice Fields
- Select — dropdown with single or multiple selection
- Checkbox — multi-select checkboxes
- Radio — single-select radio buttons
- Button Group — styled radio buttons
- True / False — toggle switch
Content Relationships
- Link — URL + label + target picker
- Page Link — select from published WordPress pages
- Post Object — select any post or custom post type
- Relationship — multi-select post picker with filtering
- Taxonomy — select terms from any taxonomy
- User — select a WordPress user
jQuery Fields
- Google Map — map picker storing lat/lng
- Date Picker — calendar date selector
- Date Time Picker — date + time selector
- Time Picker — time selector
- Color Picker — hex/rgba color picker
Media
- Image — upload or select from media library
- File — upload or select any file type
Layout & Structure (Free)
- Message — static instructional text shown in the editor
- Accordion — collapsible field section
- Tab — tabbed field layout within a group
- Group — nest fields inside a named container
Pro-Only Fields
ACF PRO adds six additional field types:
| Field | What It Does |
|---|---|
| Repeater | A set of sub-fields that editors can add any number of rows of |
| Flexible Content | Multiple named layout options, each with their own sub-fields — the foundation of page-builder-style content |
| Gallery | Multi-image gallery with sorting and captions |
| Clone | Reuse an existing field or field group inside another group |
| Options Pages | Global admin pages (not tied to a post) for site-wide settings |
| ACF Blocks | Build custom Gutenberg blocks using PHP templates + ACF fields |
ACF Free vs Pro
| Feature | Free | Pro |
|---|---|---|
| Core 30+ field types | Yes | Yes |
| Field groups + location rules | Yes | Yes |
| REST API integration | Yes | Yes |
| Custom post type / taxonomy builder | Yes | Yes |
| Local JSON (file-based sync) | Yes | Yes |
| Repeater field | No | Yes |
| Flexible Content field | No | Yes |
| Gallery field | No | Yes |
| Clone field | No | Yes |
| Options Pages | No | Yes |
| ACF Blocks (Gutenberg) | No | Yes |
| Price | Free | From $49/yr |
ACF PRO pricing (2026):
- Personal — $49/yr, 1 website
- Freelancer — $149/yr, 10 websites
- Agency — $249/yr, unlimited websites
All Pro tiers include the same features; only the site activation limit differs. Development and staging sites do not count toward your limit. ACF PRO comes with a 30-day money-back guarantee.
ACF PRO is a standalone plugin — you install it instead of the free version, not alongside it. Upgrading from free to Pro preserves all your existing field groups and data.
ACF + Custom Post Types
ACF and custom post types (CPTs) are the two pillars of structured content in WordPress. They work together:
- Custom post types define the content model — “Property”, “Team Member”, “Recipe”, “Course”
- ACF field groups define the data fields that describe each item in that model
Since ACF 6.1, you can register custom post types and taxonomies directly inside the ACF UI under ACF → Post Types and ACF → Taxonomies. No code, no separate plugin like CPT UI required.
A typical content modeling workflow with ACF:
- Go to ACF → Post Types → Add New and create a “Property” post type
- Go to ACF → Field Groups → Add New, name it “Property Details”
- Add fields: Price (Number), Bedrooms (Number), Bathrooms (Number), Square Footage (Number), Description (WYSIWYG), Photos (Gallery — Pro), Features (Repeater — Pro)
- Set the Location Rule: “Post Type is equal to Property”
- Now every Property post shows your custom fields in the editor
The same pattern works for virtually any content type: job listings, real estate, events, menus, portfolios, directories, e-learning courses, and more.
REST API and the “Show in REST API” Setting
By default, ACF field groups are not exposed to the WordPress REST API. To make a field group accessible via REST — which is required for many integrations, including AI tools — you must enable Show in REST API in the field group’s settings.
This is a per-field-group toggle. Once enabled, ACF fields for that group appear in REST API responses under the acf key on posts, users, and terms.
ACF 6.8 added another layer of AI-readiness: integration with the WordPress Abilities API, which allows external consumers (AI tools) to manage field groups, post types, and taxonomies when explicitly enabled via the enable_acf_ai feature flag.
Using ACF with AI: Easy MCP AI
Once you have structured data in ACF fields, you can interact with it through AI — reading values, updating fields at scale, and discovering your content model through natural language — using Easy MCP AI.
Easy MCP AI is a free, open-source WordPress plugin that turns your site into a fully compliant remote MCP server. It connects AI clients like Claude, ChatGPT, Cursor, and 15 others to your WordPress site through the Model Context Protocol — the open standard released by Anthropic on November 25, 2024, and donated to the Linux Foundation’s Agentic AI Foundation on December 9, 2025.
Easy MCP AI exposes 6 dedicated ACF tools as part of its full suite of 214 tools:
| Tool | What It Does |
|---|---|
| Get fields | Read ACF field values for any post or page |
| Update fields | Write ACF field values to any post or page |
| Get term fields | Read ACF fields on a taxonomy term |
| Get user fields | Read ACF fields on a WordPress user profile |
| Update user fields | Write ACF fields on a user profile |
| List field groups | Enumerate registered field groups so the AI knows what fields exist |
The AI-to-ACF workflow complements the ACF MCP guide, which covers the REST API requirement and connection setup in detail. The short version: enable Show in REST API on each field group you want accessible, then Easy MCP AI handles the rest — no additional configuration.
What You Can Ask an AI After Connecting
With Easy MCP AI connected to Claude (or any other supported client), you can work with ACF data at a scale that would be tedious to do by hand:
- “List all my ACF field groups.”
- “Read the custom fields on my 10 most recent Property posts.”
- “Set the ‘status’ field to ‘sold’ on all Properties in the Downtown neighborhood.”
- “Update the ‘bio’ ACF field for every user with the Editor role.”
- “What fields exist on my Team Member post type?”
Everything runs through your own WordPress server. Credentials are encrypted AES-256-GCM with per-provider HKDF-derived keys. No data leaves your server unless Claude actively calls a tool.
Setup is four steps: install Easy MCP AI → enable the ACF integration under Easy MCP AI → Plugins → copy your MCP URL from Easy MCP AI → Dashboard → add it as a custom connector in your AI client and authorize via OAuth.
Key Facts
- ACF is free and open source, maintained by WP Engine; the free version is available at wordpress.org/plugins/advanced-custom-fields
- ACF powers over 3 million WordPress sites (per wordpress.org listing)
- The free version ships with over 30 field types; Pro adds Repeater, Flexible Content, Gallery, Clone, Options Pages, and ACF Blocks
- ACF PRO pricing starts at $49/yr for 1 site; $149/yr for 10 sites; $249/yr for unlimited sites
- ACF field groups are not exposed to the REST API by default — you must enable “Show in REST API” per field group
- Since ACF 6.1, you can register custom post types and taxonomies directly in the ACF UI — no code required
- ACF 6.8 (released March 2026) added native integration with the WordPress Abilities API, making ACF data more accessible to AI tools
- The current stable version is 6.8.4 (released June 10, 2026)
- Easy MCP AI exposes 6 ACF tools for reading and writing field data across posts, users, terms, and field groups
Conclusion
Advanced Custom Fields is the most widely used structured content plugin in the WordPress ecosystem for good reason: it makes content modeling accessible without sacrificing depth. The free version covers most use cases with 30+ field types and a clean field group builder. Pro unlocks the fields — Repeater, Flexible Content, Options Pages — that underpin the most ambitious WordPress builds.
Pair ACF with custom post types and you have a proper CMS. Pair it with Easy MCP AI and you have a CMS your AI assistant can read and write at scale.
→ Get Easy MCP AI from the WordPress plugin directory