A JSON-LD generator takes your content data through a web form and outputs ready-to-use structured data code. No knowledge of JSON syntax required. This guide explains how generators work, compares the best free options, and shows you how to customise the output to unlock more rich result properties than the default templates provide.

1. What JSON-LD Generators Actually Produce

Every JSON-LD generator outputs a block with the same four parts:

<script type="application/ld+json">      ← script wrapper
{
  "@context": "https://schema.org",     ← vocabulary declaration
  "@type":    "Article",                ← type from form dropdown
  "headline": "Your Article Title",     ← properties from form inputs
  "datePublished": "2026-02-25",
  "author": { "@type": "Person", "name": "Jane Doe" }
}
</script>

2. Best Free JSON-LD Generators Compared

Tool	Best For	Types Supported	Validates Output?
SchemaValidator.org	Validate generated output instantly	All types	✅ Yes
Merkle JSON-LD Generator	Beginners, form-based	10 common types	⚠️ Basic only
Hall Analysis Generator	Advanced users, all properties	50+ types	❌ No
JSON-LD Playground	Developers testing custom code	All types	✅ Syntax only
Yoast SEO / RankMath	WordPress users	Site-wide + post types	✅ Via GWT integration

3. Step-by-Step: Using a JSON-LD Generator

Select your schema type

Match the type to the page content. If your page is a product listing, choose Product. If it's a blog post, choose Article. If you're not sure, check Google's rich results gallery for inspiration.

Fill in required fields first

Complete every field marked as required (*). These are the minimum properties needed for Google to recognise the type. Missing required fields means no rich result.

Add recommended properties

After required fields, add as many recommended properties as you have data for. Each additional property increases the richness of the result Google can display.

Copy the generated JSON-LD

Copy the output. Do not modify the JSON structure — only change values. If you break the JSON syntax (e.g. missing a closing brace), the schema will be ignored.

Validate immediately

Paste the output into SchemaValidator.org before deploying. Fix all red errors. Green = safe to deploy.

Add to page and verify live

Paste into the <head> of your page. After deploying, use the Google Rich Results Test to confirm the schema is detectable from the live URL.

4. How to Customise Generator Output

Most generators output the bare minimum. To maximise rich result coverage, add properties beyond what the form includes. Here is a typical generator output for a Product, and the improved version:

❌ Minimal generator output

{
  "@context": "https://schema.org",
  "@type": "Product",
  "name": "Ergonomic Chair",
  "description": "Comfortable office chair",
  "offers": {
    "@type": "Offer",
    "price": "299.00",
    "priceCurrency": "USD"
  }
}

✅ Enriched version

{
  "@context": "https://schema.org",
  "@type": "Product",
  "name": "Ergonomic Chair",
  "description": "Comfortable office chair",
  "image": "https://example.com/chair.jpg",
  "brand": {
    "@type": "Brand",
    "name": "ErgoPlus"
  },
  "sku": "CHAIR-001",
  "offers": {
    "@type": "Offer",
    "price": "299.00",
    "priceCurrency": "USD",
    "availability":
      "https://schema.org/InStock",
    "url": "https://example.com/chair",
    "priceValidUntil": "2026-12-31",
    "shippingDetails": {
      "@type": "OfferShippingDetails",
      "shippingRate": {
        "@type": "MonetaryAmount",
        "value": "0",
        "currency": "USD"
      },
      "deliveryTime": {
        "@type": "ShippingDeliveryTime",
        "handlingTime": {
          "@type": "QuantitativeValue",
          "minValue": 0, "maxValue": 1,
          "unitCode": "DAY"
        }
      }
    }
  },
  "aggregateRating": {
    "@type": "AggregateRating",
    "ratingValue": "4.7",
    "reviewCount": "312"
  }
}

5. Generating Multiple Schema Types on One Page

Most generators build a single schema block. But many pages benefit from multiple JSON-LD blocks — for example, a blog post that needs Article + BreadcrumbList + FAQPage + Author entity. You can include multiple JSON-LD scripts on one page:

<!-- Multiple JSON-LD blocks on a single page is valid -->
<script type="application/ld+json">
{ "@context": "https://schema.org", "@type": "Article", ... }
</script>

<script type="application/ld+json">
{ "@context": "https://schema.org", "@type": "BreadcrumbList", ... }
</script>

<script type="application/ld+json">
{ "@context": "https://schema.org", "@type": "FAQPage", ... }
</script>

<!-- Or reference them from a @graph array in one block -->
<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@graph": [
    { "@type": "Article", ... },
    { "@type": "BreadcrumbList", ... },
    { "@type": "FAQPage", ... }
  ]
}
</script>

6. Validating Generator Output: What to Check

Not all generators produce correct output. Here are the most common generator errors you should catch before deploying:

🚩 price as a number instead of string

"price": 19.99 (wrong) vs "price": "19.99" (correct)

Schema.org Offer.price must be a string. Generators that output it as a JSON number will fail validation. This is one of the most common generator errors.

🚩 Missing @context on nested schema types

Only the root level needs @context. Nested objects should NOT repeat it.

Some generators incorrectly duplicate @context inside nested entities like author, offer, and publisher. This creates bloated, non-standard JSON-LD.

🚩 author as a plain string instead of a Person entity

"author": "Jane Doe" (wrong) vs "author": { "@type": "Person", "name": "Jane Doe" } (correct)

The author property expects a Thing entity, not a plain string. Generators that output a string will trigger validation warnings.

🚩 Empty required fields left from the template

"name": "" or "price": null

Generators often output the full property list with empty values for fields you didn't fill in. Delete any property where the value is empty or null — empty values are treated as errors.

🚩 Absolute vs relative URL confusion

"url": "/products/widget" (wrong) vs "url": "https://example.com/products/widget" (correct)

All URL properties in JSON-LD must be absolute URLs with the full domain. Relative paths are not valid.

7. When to Use a Generator vs Write Schema by Hand

Situation	Use generator?	Why
First-time implementation of a new schema type	✅ Yes	Generator gives you the correct property structure without needing to memorise the spec
Customising output with dynamic values (prices, dates)	⚠️ Partial	Use generator to get the structure, then replace static values with dynamic variables in your CMS template
Complex entity graphs (@id, @graph, cross-references)	❌ No	Generators do not understand entity relationships. Write entity-linked schema by hand from a template.
Bulk templated pages (product pages, event listings)	❌ No	Write a single hand-crafted template per page type, then populate dynamically from your CMS data model.
Quick one-off pages (press release, event, job posting)	✅ Yes	Low-frequency use cases where writing by hand is slower than the generator workflow.

Frequently Asked Questions

Are free JSON-LD generators accurate enough for production use? ▼

Most reputable free generators produce structurally valid JSON-LD, but they only cover the most common properties. The output is a starting template, not a finished implementation. For production use: (1) always validate the output against a schema validator before deploying, (2) add any additional recommended properties the form did not offer, (3) replace any static/example values with your real dynamic data. A generator that passes validation is a reliable starting point.

What is the difference between a JSON-LD generator and a schema validator? ▼

A generator creates JSON-LD code from form inputs — you fill in values and it outputs the markup. A validator checks whether existing JSON-LD code is correct — you paste or URL-test code and it reports errors, warnings, and rich result eligibility. They serve opposite workflow directions. Best practice: use a generator to create initial code, then immediately validate the output before deploying it.

Can I use a JSON-LD generator for any schema.org type? ▼

Generators only support the types their authors have built forms for — typically 10–50 types depending on the tool. For any type beyond those, you need to write the JSON-LD by hand using the schema.org documentation. The most complete reference for all properties of any type is schema.org itself — find your type (e.g. schema.org/MusicEvent), click through to see all expected properties, and build the JSON-LD manually following the standard property/value format.

How do I add generated JSON-LD to a WordPress site without a plugin? ▼

In WordPress, go to Appearance → Theme Editor → header.php (or your child theme's header). Paste the JSON-LD script block inside the <head> section, above the closing </head> tag. Alternatively, use a code snippet plugin (Code Snippets, WPCode) to inject it on specific pages without editing theme files — safer for updates. If using Yoast or RankMath, those plugins have a custom schema code field per-post — paste your generated JSON-LD there instead.

Should I use @graph or multiple script blocks for multiple schema types? ▼

Both are valid and Google processes both correctly. @graph (a single script block with an array) is cleaner — it allows entity cross-referencing using @id, which creates stronger entity relationships in the Knowledge Graph. Multiple separate script blocks are simpler to generate and easier to read. For basic implementations (no cross-entity linking needed), use multiple script blocks. For advanced entity-linked schemas (Organization linked to Article linked to Author), use @graph.

A generator output passed validation but I still see no rich results. Why? ▼

Schema validation checks syntax and required properties — it does not guarantee Google will display rich results. Rich results also require: (1) Google must have crawled and indexed the page recently, (2) the page must meet Google's content quality bar for that rich result type, (3) some rich results (like FAQ dropdowns) have been de-emphasised by Google since 2023 and appear less frequently, (4) Google may decide a competitor deserves the rich result slot more. Passing validation is necessary but not sufficient for rich result display.

Can generated schema be different on the same URL for different users? ▼

No — the JSON-LD injected into the HTML must reflect the canonical, publicly accessible version of the page. Google's crawler (Googlebot) always sees the page as an unauthenticated user. If your schema shows different prices for logged-in vs anonymous users, Google sees only the anonymous price. Never server-render personalised schema — your schema should always reflect what every user sees when they land on the page from a Google search result.

Is there a generator for LocalBusiness schema with multiple locations? ▼

Most generators only support a single LocalBusiness entity per form. For multi-location businesses, generate the schema for one location, then duplicate and modify the JSON-LD for each additional location — changing name (if different), address, telephone, geo, and url for each location page. Each location should have its own dedicated page with its own LocalBusiness JSON-LD. Do not put all locations in a single JSON-LD block on the homepage — each needs to live on its own indexable, specific page.

Validate Your JSON-LD Output

Paste your generator output. We'll instantly show every error, warning, and which rich results you're eligible for.

Validate JSON-LD →

Related Guides

→ What is JSON-LD?

Understand the JSON-LD format before generating it

→ Schema Markup Checker Tools

Best tools to validate your generated JSON-LD

→ Article vs BlogPosting Schema

Which Article subtype to pick in the generator

→ What is Structured Data?

Why JSON-LD generators matter for your SEO strategy

→ Google Rich Results Guide

What each schema type unlocks in Google Search

→ Schema Markup Tutorial

Step-by-step implementation guide for all schema types

JSON-LD Generator: Create Structured Data Code Instantly