The wrong schema tool gives you brittle markup. The right one fits the team maintaining it.

Best for: One-off JSON-LD for the common schema types

Built by Max Prin. The tool page now carries dentsu branding; Merkle is a dentsu company. Most-cited free generator in the SEO world. Live JSON-LD preview as you fill the form, covers Article, FAQ, HowTo, LocalBusiness, Product, Event, Job Posting and a handful more. No save state, no built-in validation - you copy out, validate elsewhere. Two things to watch: it still offers FAQ, How-to and Sitelinks Searchbox forms, all rich results Google no longer shows, and its test link still points at Google's old Structured Data Testing Tool, which now just redirects to Google's docs. Test in the Rich Results Test instead.

Best for: Developers who want the deepest type coverage in a free tool

Rebuilt April 2026 (v2.0). Coverage jumped from 3 types to 17, including LocalBusiness with 100+ sub-types (Restaurant, Hotel, Dentist, Plumber and the rest of the chain). Live required-field validation, form state persists between visits, terminal-style UI for developers. Use this if Merkle is too thin and Schema App is too heavy. Skip its WebSite option if you only wanted the sitelinks search box: Google removed that feature in November 2024.

Best for: Quick generation aimed at Google rich results only

Free form-based generator. Cleaner output than Merkle for some types but narrower coverage. Worth knowing about as a fallback when Merkle's field set doesn't match what you need. Its Validate button still sends you to Google's retired Structured Data Testing Tool, so paste the output into the Rich Results Test yourself.

Best for: Sites with thousands of pages needing dynamic injection and a knowledge graph

The enterprise standard. Visual editor for non-developers, dynamic schema injection across templated pages, deep WooCommerce integration on the WP side, full knowledge-graph management on the platform side. Overkill for a five-page brochure site, the right call when schema needs to scale across an estate. Pricing, re-checked October 2026: the basic WordPress plugin is free. Schema App's support pages still put the Advanced WordPress plugin at $30 a month within a Pro subscription, but the Pro subscription page now redirects to custom-quote pricing with a one-time setup fee, a 12-month minimum and no free trial. Ask for a quote before you budget.

Best for: Entity-driven schema (About, Mentions, sameAs)

The strongest tool for the entity layer: auto-generates About and Mentions properties and connects them to Wikipedia and other authoritative sources via sameAs. Not where you go for Product or HowTo - where you go when you want a page's entities surfaced explicitly for semantic search and AI extraction. There is a limited free plan; Freelancer starts at $49 a month and Agency at $196 a month.

Best for: WordPress sites needing flexible sitewide schema

Most flexible WP schema plugin. 16+ schema types in the free plugin (per its WordPress.org listing), with 20+ pre-defined types, schema templates and custom schema in PRO. PRO is €7.99 a month billed yearly (€95.88) ex VAT for unlimited personal sites, renewing at €8.99 a month. Rank Math shows prices in a currency based on where you are, so you may see a different figure. Strong on Article, Product, FAQ, HowTo, LocalBusiness. Default WP pick for content sites that want schema set once and applied across post types.

Best for: WordPress sites already running Yoast

Yoast's schema features, including Schema Aggregation, are in the free Yoast SEO plugin. It builds a connected schema graph that links page entities (Article, BreadcrumbList) to site-level entities (Organization, WebSite). Schema Aggregation (free since 3 March 2026, version 27.1) is an opt-in feature that publishes your whole site's schema in one place. You do not need Premium for schema. Premium is listed at $118.80 a year ex VAT, and Yoast's page lets you switch currency. Good if Yoast is already the setup. Less compelling as a schema-specific pick versus Rank Math.

Best for: Beginner-friendly schema on WordPress

Schema generator built into the All In One SEO plugin. Catalog of 20+ schema types, custom schema support and a built-in validator. It now has an AI Schema Generator too: Smart Schema reads your page and picks a type, Prompt-Based Schema builds JSON-LD from a description. Basic covers one site at $49.50 for the first year and renews at $99. The most beginner-friendly WP option - if Rank Math feels too dense, this is the alternative.

Best for: Set-once, forget sitewide schema on WordPress

Lighter than Rank Math but easier to configure. Built by Brainstorm Force, the team behind the Astra theme. Useful for sites that want global schema rules applied once and left alone. Both licences cover unlimited sites: annual is $69 on introductory pricing and renews at $79, lifetime is $229.

Best for: Checking the author and publisher chain alongside Google's tests

Free tool I run on this site. Checks the author/publisher chain, Person and Organization completeness and FAQ structure. Google says structured data is not required for its AI features, but it still helps pages qualify for rich results. Use it alongside Google's Rich Results Test and the Schema.org Validator. None of the three on its own is enough.