JSON-LD vs Microdata vs RDFa: Which Schema Format Should You Use in 2025?

When implementing schema markup, one of the first decisions you'll face is choosing the right format. There are three main options: JSON-LD, Microdata, and RDFa. Each has advantages, limitations, and specific use cases. While Google strongly recommends one format over the others, understanding all three helps you make informed decisions for your website's structured data strategy.

What Are Schema Markup Formats?

Schema markup formats are different syntaxes for adding structured data to web pages. All three formats use the same schema.org vocabulary to describe content, but they differ significantly in how that data is integrated into your HTML. The format you choose affects implementation complexity, maintenance requirements, and compatibility with search engines and other systems.

JSON-LD: JavaScript Object Notation for Linked Data

JSON-LD is Google's recommended format for structured data. It uses JavaScript notation and is added to pages in a <script> tag, completely separate from HTML content.

JSON-LD Example

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Product",
  "name": "Wireless Headphones",
  "offers": {
    "@type": "Offer",
    "price": "299.99",
    "priceCurrency": "USD"
  }
}
</script>

Advantages of JSON-LD

Separation of Concerns: Schema markup is completely independent of HTML, making it easier to maintain
Easier Implementation: Can be added to <head> or <body> without modifying existing HTML structure
Better for Dynamic Content: JavaScript can generate or modify JSON-LD on the fly based on page state
Google's Recommendation: Explicitly recommended by Google for all schema types
Cleaner Code: Doesn't clutter HTML with additional attributes and markup
Easier Debugging: Self-contained blocks are simpler to validate and troubleshoot
CMS Friendly: Easy to add via plugins or template modifications without touching content areas

Disadvantages of JSON-LD

Data Duplication: Information must exist both in HTML content and JSON-LD, creating potential for mismatches
Synchronization Required: Schema must be updated whenever page content changes
Slightly Larger Page Size: Adds extra bytes since data is represented twice (in HTML and schema)
Learning Curve: Requires understanding JSON syntax and structure

Microdata: Inline HTML Attributes

Microdata embeds schema markup directly into HTML tags using special attributes like itemscope, itemtype, and itemprop. It was once Google's recommended format before JSON-LD.

Microdata Example

<div itemscope itemtype="https://schema.org/Product">
  <h1 itemprop="name">Wireless Headphones</h1>
  <div itemprop="offers" itemscope itemtype="https://schema.org/Offer">
    <span itemprop="price">299.99</span>
    <span itemprop="priceCurrency">USD</span>
  </div>
</div>

Advantages of Microdata

No Data Duplication: Schema describes existing HTML content directly, no separate data block needed
Automatic Synchronization: When HTML content changes, schema automatically reflects those changes
Semantic HTML: Makes HTML more meaningful and machine-readable
Lighter Page Weight: Doesn't add a separate data block, just attributes to existing elements
Visual Mapping: Clear relationship between visible content and schema markup

Disadvantages of Microdata

HTML Complexity: Clutters HTML with additional attributes, making code harder to read and maintain
Difficult Retrofitting: Adding microdata to existing sites requires modifying all relevant HTML elements
CMS Challenges: More difficult to implement in content management systems without direct HTML access
Harder Debugging: Schema errors may be scattered throughout HTML rather than in one location
Template Dependency: Requires access to and modification of HTML templates
Not Google's Preference: While supported, Google recommends JSON-LD instead

RDFa: Resource Description Framework in Attributes

RDFa is another inline markup format that uses attributes like vocab, typeof, and property. It's more flexible than microdata but also more complex.

RDFa Example

<div vocab="https://schema.org/" typeof="Product">
  <h1 property="name">Wireless Headphones</h1>
  <div property="offers" typeof="Offer">
    <span property="price">299.99</span>
    <span property="priceCurrency">USD</span>
  </div>
</div>

Advantages of RDFa

Flexibility: Can describe complex relationships and multiple entities more easily than microdata
W3C Standard: Official W3C recommendation with strong specification support
Multiple Vocabularies: Can mix schema.org with other vocabularies in the same markup
No Duplication: Like microdata, describes existing content without separate data blocks

Disadvantages of RDFa

Complexity: More complex syntax than microdata, steeper learning curve
Limited Adoption: Less commonly used than JSON-LD or microdata for schema.org
HTML Clutter: Like microdata, adds attributes throughout HTML
Not Google's Recommendation: Google suggests JSON-LD for better performance and simplicity
Debugging Difficulty: Complex nested structures can be hard to validate and troubleshoot

Google's Official Recommendation

Google strongly recommends JSON-LD for structured data implementation. While the search engine supports all three formats, JSON-LD is preferred because it's easier to implement, maintain, and debug. Google's documentation primarily uses JSON-LD examples, and their testing tools provide better support for this format.

Google's official stance: "We recommend using JSON-LD for structured data whenever possible." This recommendation applies to all schema types: Product, Article, FAQ, Event, Review, and all others.

When to Use Each Format

Use JSON-LD When:

Starting fresh schema implementation on any website
Working with WordPress or other CMS platforms
Implementing schema across multiple page types
You want the easiest maintenance and updates
Following Google's best practices is a priority
Using schema generators or automation tools
You need to add schema without modifying HTML content

Use Microdata When:

You have direct control over HTML templates and prefer semantic markup
Data synchronization between content and schema is a major concern
Working with legacy systems already using microdata
You want the absolute lightest-weight implementation
Building simple, static pages with straightforward schema needs

Use RDFa When:

Working with systems that specifically require or generate RDFa
Needing to combine schema.org with other RDF vocabularies
Maintaining existing sites already using RDFa extensively
Working in academic or publishing environments with RDF requirements

Can You Mix Formats on the Same Site?

Technically yes, you can use different schema formats on different pages or even combine them on the same page. However, this is generally not recommended because:

Increases complexity and maintenance burden
Makes auditing and debugging more difficult
Can create confusion about which format to use for new content
May lead to duplicate or conflicting schema on the same page

Best practice: Choose one format (JSON-LD recommended) and use it consistently across your entire site.

Migrating from Microdata or RDFa to JSON-LD

If you currently use microdata or RDFa and want to migrate to JSON-LD:

Audit existing schema to understand what types and properties you're currently using
Create JSON-LD equivalents for each page type with schema markup
Test JSON-LD implementation thoroughly using Rich Results Test
Add JSON-LD while keeping existing microdata/RDFa temporarily
Monitor Search Console to verify Google processes new JSON-LD correctly
Once confirmed working, remove old microdata/RDFa markup
Continue monitoring to ensure no drop in rich result appearances

Performance Considerations

All three formats have minimal performance impact, but there are subtle differences:

JSON-LD adds extra bytes since data is duplicated, but this is typically negligible (1-3KB per page). The benefit of easier implementation and maintenance far outweighs the minimal size increase. Modern compression techniques further minimize any performance impact.

Microdata and RDFa add attributes to existing HTML, resulting in slightly smaller total page size. However, they increase HTML complexity, which can slow down development and maintenance—a far greater cost than a few kilobytes.

Tools and Resources for Each Format

JSON-LD Tools

SchemaBooster: AI-powered JSON-LD generator for all schema types
Google's Structured Data Markup Helper: Generates JSON-LD from content
Schema.org JSON-LD Generator: Online tool for creating schema markup
WordPress SEO Plugins: Yoast, RankMath, Schema Pro with JSON-LD support

Microdata Tools

Google's Structured Data Markup Helper: Can generate microdata
Schema Creator: Browser extensions for inline microdata editing
Microdata generators: Various online tools for manual microdata creation

The Verdict: Which Format Should You Use?

For 99% of websites, JSON-LD is the clear winner. It's Google's recommended format, easier to implement and maintain, works seamlessly with CMS platforms, and provides the best long-term scalability. Unless you have specific technical requirements for microdata or RDFa, start with JSON-LD and stick with it.

The SEO benefits of properly implemented schema markup are identical regardless of format—Google treats them equally when determining rich result eligibility. The difference lies in implementation complexity and maintenance burden, where JSON-LD excels.

Conclusion

While JSON-LD, microdata, and RDFa all accomplish the same goal of adding structured data to web pages, JSON-LD stands out as the most practical choice for modern websites. Its separation from HTML content, ease of implementation, and Google's explicit recommendation make it the format of choice for SEO professionals and developers alike.

Focus your energy on creating accurate, comprehensive schema markup rather than debating formats. Choose JSON-LD, implement it correctly, and you'll reap the SEO benefits of structured data without unnecessary complexity.