JSON-LD vs Microdata vs RDFa compared — pros, cons, and why Google recommends JSON-LD. With the same example in all three.
Use JSON-LD — it's the format Google explicitly recommends, it's the easiest to add and maintain over time, and it keeps your structured data cleanly separate from your visible HTML. Microdata and RDFa embed their labels directly inside your page's tags, which works just as well technically but is genuinely harder to manage and maintain at any real scale. Here's the full comparison, with the same product data written out in all three formats side by side.
What Is JSON-LD?
JSON-LD (JSON for Linked Data) is a way of writing structured data as a single, self-contained block of JSON, wrapped in a <script type="application/ld+json"> tag. It sits apart from your visible HTML entirely — a crawler reads it as a distinct block of facts about the page, and a browser's rendering of the page never touches it at all. That separation is JSON-LD's defining advantage: you can add, edit, generate, or template your structured data without ever risking the markup that controls how the page actually displays.
The Same Data, Three Formats
JSON-LD (recommended) — a separate script block, entirely apart from the visible markup:
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "Product",
"name": "Wireless Headphones",
"offers": { "@type": "Offer", "price": "4999", "priceCurrency": "INR" }
}
</script>
Microdata — attributes (itemscope, itemtype, itemprop) woven directly into your existing HTML tags:
<div itemscope itemtype="https://schema.org/Product">
<span itemprop="name">Wireless Headphones</span>
<span itemprop="price">4999</span>
</div>
RDFa — similar in spirit to Microdata, but using vocab, typeof, and property attributes instead:
<div vocab="https://schema.org/" typeof="Product">
<span property="name">Wireless Headphones</span>
<span property="price" content="4999">₹4,999</span>
</div>
All three describe exactly the same fact — a Product named "Wireless Headphones" priced at ₹4,999 — and all three are read correctly by Google. The difference between them is entirely in where the data physically lives and how easy it is to maintain over the life of the page, not in what a search engine or an AI crawler can actually extract from it once parsed.
What Is Microdata vs RDFa? (Where They Came From)
Both Microdata and RDFa predate JSON-LD as widely used structured-data formats, and both work by attaching semantic attributes directly to the HTML elements that already display the content. Microdata is the simpler of the two, using itemscope/itemtype/itemprop attributes and originating alongside the HTML5 specification. RDFa (Resource Description Framework in Attributes) is older and more flexible — it comes from the broader Linked Data / Semantic Web world and supports more complex relationships between data, using vocab, typeof, and property attributes. In practice, for the schema.org use cases most sites care about (Product, Article, FAQ, LocalBusiness), Microdata and RDFa accomplish almost the same thing through slightly different attribute syntax.
Full Comparison
| JSON-LD | Microdata | RDFa | |
|---|---|---|---|
| Where it lives | Separate <script> block |
Attributes inside HTML tags | Attributes inside HTML tags |
| Ease of adding | Easiest — one self-contained block | Harder — requires editing every relevant tag | Harder — same as Microdata |
| Ease of maintaining | Simple — update one block, page markup untouched | Tangled with visible markup; risky to edit | Tangled with visible markup; risky to edit |
| Risk of breaking the page | None — it's not rendered | Higher — a typo can affect visible layout | Higher — same risk as Microdata |
| Templating / automation | Very easy to generate programmatically | Harder to template cleanly | Harder to template cleanly |
| Google's stated preference | Recommended | Supported | Supported |
| Best for | Any modern site, especially CMS-driven ones | Legacy implementations already in place | Semantic Web / Linked Data use cases beyond SEO |
Why Google Prefers JSON-LD
Google has stated a clear preference for JSON-LD, and the reasoning holds up in practice. Because it's decoupled from the visible HTML, JSON-LD can be added, edited, or generated without touching your page's actual structure — which means less risk of accidentally breaking your layout while adding structured data, and much easier automation (a CMS can inject a JSON-LD block per page template without touching the surrounding HTML at all). It's also the easiest format to inject via a tag manager, since a Custom HTML tag can drop in a self-contained script without needing to reach into specific elements on the page. Microdata and RDFa still validate and still work, but neither offers that separation.
Does It Matter Which Format You Use for Rankings?
No — none of the three formats affects rankings differently. Google parses valid JSON-LD, Microdata, and RDFa equally well for eligibility purposes; the choice is entirely about ease of implementation and maintenance, not about which one Google "counts" more. See does schema markup help SEO for the deeper answer on how schema affects rankings at all.
When You Might Still See Microdata or RDFa
Some older sites, certain WordPress themes with hardcoded microdata baked into their templates, or content-management systems built before JSON-LD became the norm, still output Microdata by default. If that's your situation, it's not urgent to rip it out — Google still reads it — but there's no reason to add new schema in Microdata or RDFa going forward. If you're doing a redesign or migration anyway, moving to JSON-LD is worth the small effort for the maintenance benefits above.
Handling Complex, Nested Data: Where the Formats Diverge Most
The comparison gets more concrete once you move past a simple Product example into something with real nesting — a Product with an Offer, which itself has a Seller, which itself has an address. In JSON-LD, this is naturally nested JSON: an object inside an object inside an object, exactly as you'd expect from any JSON structure, and exactly how the Schema Markup Generator outputs it.
{
"@context": "https://schema.org",
"@type": "Product",
"name": "Wireless Headphones",
"offers": {
"@type": "Offer",
"price": "4999",
"priceCurrency": "INR",
"seller": { "@type": "Organization", "name": "Example Store" }
}
}
In Microdata, the same nesting requires a new itemscope for every nested object, attached to a wrapping HTML element that may not otherwise need to exist — meaning your visible markup can end up with extra <div> or <span> wrappers whose only purpose is to hold an itemprop attribute, not to serve any visual or semantic role in your layout:
<div itemscope itemtype="https://schema.org/Product">
<span itemprop="name">Wireless Headphones</span>
<div itemprop="offers" itemscope itemtype="https://schema.org/Offer">
<span itemprop="price">4999</span>
<div itemprop="seller" itemscope itemtype="https://schema.org/Organization">
<span itemprop="name">Example Store</span>
</div>
</div>
</div>
This is the practical reason JSON-LD wins out as data gets more complex: nesting in JSON is just... nesting. Nesting in Microdata or RDFa means adding structural HTML elements purely to carry attributes, which can start to interfere with your actual CSS layout if you're not careful about which elements you're allowed to add without breaking visual design.
Does the Format Affect Page Performance?
Marginally, and not in a way that should drive the decision. A JSON-LD block adds a small amount of extra markup to the page's HTML — typically a few hundred bytes to a few kilobytes depending on how much you're describing — but it's not render-blocking and doesn't affect Core Web Vitals in any meaningful way for the vast majority of sites. Microdata and RDFa, by attaching attributes to elements that already exist, technically add less raw byte weight per fact described, but the difference is negligible next to almost any other factor affecting page speed (image sizes, JavaScript bundles, font loading). Choose based on maintainability, not on a performance difference that doesn't meaningfully exist in practice.
Which Format Do Search Engines Actually Parse Most Reliably?
All three are parsed reliably by Google when written correctly — the failure mode with any format is almost always a mistake in how it was written, not the format itself rejecting valid data. JSON-LD has a practical edge here too, though: because it's a single self-contained block, a validator (or a person debugging by eye) can immediately see the entire structured-data payload for a page in one place. With Microdata or RDFa, the same information is scattered across however many HTML elements it touches, which makes visually auditing "what does this page currently claim" meaningfully harder — not impossible, just slower.
Just Use JSON-LD
Unless you have a specific legacy reason to stick with Microdata or RDFa, generate JSON-LD with the Schema Markup Generator and paste it in. It builds valid, correctly nested JSON-LD from a typed form so you never have to hand-write the brackets — see how to add schema markup for the full step-by-step across WordPress, Shopify, and other platforms.
A Real Migration Example: Converting Microdata to JSON-LD
Say you've inherited a WordPress theme that hardcodes Microdata attributes into every product template — a common situation with older or budget themes. The practical migration path: first, identify every schema.org type the existing Microdata declares (usually visible by searching the theme's template files for itemtype="https://schema.org/), then recreate each one as an equivalent JSON-LD block using the Schema Markup Generator, and add the new JSON-LD via a plugin field or Google Tag Manager rather than editing the theme files directly. You do not need to strip the old Microdata attributes out of the HTML immediately — having both present isn't a conflict as long as they describe the same facts consistently — but plan to remove the legacy Microdata during your next theme update or redesign, once the JSON-LD is confirmed working, so you're not maintaining two parallel sources of the same information indefinitely.
Tooling and Editor Support
Most modern SEO plugins (Yoast, Rank Math), page builders, and headless CMS platforms default to outputting JSON-LD when they generate schema automatically, which is a large part of why it's become the de facto standard in practice, not just in Google's stated preference. Code editors and IDEs also tend to offer better JSON syntax validation and auto-formatting out of the box than they do for attributes embedded in HTML, which matters if you're hand-editing or reviewing schema regularly — a stray missing comma in JSON-LD is easier to spot in a formatted code block than a missing itemprop attribute buried in a long line of HTML.
What About Other Structured-Data Formats You Might Encounter?
Beyond JSON-LD, Microdata, and RDFa, you may occasionally encounter older or more niche approaches — a hand-rolled <meta> tag scheme predating Schema.org entirely, or a CMS-specific proprietary format that gets translated into one of the three standard formats at render time. These aren't a fourth real option for new implementations; they're either legacy or an abstraction layer that ultimately outputs JSON-LD, Microdata, or RDFa anyway. If you inherit a site using something unfamiliar, the practical step is the same regardless: check what actually renders in the page's HTML source, and treat that as the real structured data, whatever the CMS's internal terminology calls it.
How to Check Which Format a Site Is Currently Using
If you're inheriting a site and don't know offhand which format is already in place, the check takes under a minute: view the page's source (not the rendered DOM, since some frameworks inject markup client-side in ways that can obscure this) and search for application/ld+json (JSON-LD), itemscope (Microdata), or typeof= combined with vocab= (RDFa). It's entirely possible to find more than one format in use across different parts of the same site — a WordPress theme's built-in Microdata alongside a plugin's JSON-LD output, for instance — which isn't itself broken, but is worth knowing about before you start adding anything new.
A Note on RDFa's Broader Use Beyond SEO
It's worth acknowledging RDFa exists for reasons beyond search engine optimization — it comes from the Linked Data / Semantic Web tradition, and some organizations (particularly in publishing, government, and academic data) use it for broader data-interchange purposes that predate and extend past what Schema.org or Google's rich results care about. If your organization already has an RDFa implementation serving one of those broader purposes, that's a different conversation from "what should I use for SEO schema markup going forward" — the SEO-specific answer (JSON-LD) still holds for any new Schema.org markup you're adding for search purposes, even if RDFa continues serving its original broader role elsewhere on the same site.
What Happens If You Use the "Wrong" Format Anyway
Nothing catastrophic — this is worth saying plainly, since the tone of most format comparisons can imply a bigger stakes than actually exist. Google reads and credits valid Microdata and RDFa the same as JSON-LD for rich-result eligibility; choosing the "wrong" format costs you maintainability over time, not eligibility today. If a legacy Microdata implementation is working correctly and validating cleanly, there's no urgency to rip it out purely on principle — the priority is simply that any new schema work defaults to JSON-LD rather than extending an older pattern further.
A Simple Decision Rule
If you remember nothing else from this comparison: for any new schema markup on any new project, default to JSON-LD without spending more time deliberating. Reach for Microdata or RDFa only if you've inherited a site where it's already deeply embedded in the theme and a full migration isn't justified yet — and even then, treat it as something to phase out at the next natural opportunity (a redesign, a theme update) rather than something to keep building on.
Frequently Asked Questions
Does Google prefer JSON-LD?
Yes — Google has explicitly stated JSON-LD is its recommended structured-data format, primarily because it's easier to add, template, and maintain without risking the page's visible markup.
What is JSON-LD, in simple terms?
A self-contained block of JSON, wrapped in a <script type="application/ld+json"> tag, that describes your page's content to search engines using the Schema.org vocabulary — separate from the HTML that controls what visitors actually see.
What's the difference between JSON-LD and Microdata?
JSON-LD lives in a separate script block; Microdata embeds attributes directly inside your existing HTML tags. JSON-LD is easier to manage because updating it never risks your page's visible layout.
Microdata vs RDFa — what's the actual difference?
Both attach structured-data attributes directly to HTML elements. Microdata uses itemscope/itemtype/itemprop and is simpler; RDFa uses vocab/typeof/property and supports more complex relationships, originating from the broader Linked Data ecosystem rather than HTML5 specifically.
Which is the best schema format overall?
JSON-LD, for nearly every modern use case — it's the easiest to implement, safest to maintain, and Google's explicitly recommended format.
Can I mix formats on one page?
It's best not to. Pick one format (JSON-LD) per schema type to avoid conflicting or duplicate structured data describing the same content.
Do I need to convert existing Microdata to JSON-LD?
Not urgently — Google still reads valid Microdata. But there's no reason to add new markup in that format, and converting during a redesign is worth the small effort for long-term maintainability.
Is JSON-LD harder to implement than Microdata?
No — it's generally easier, especially with a generator, since you're filling in a form and copying one block rather than manually editing multiple HTML attributes across your page.
Does the choice of format affect how AI search engines read my structured data?
No — the same logic applies as with classic search: AI systems that parse Schema.org markup read JSON-LD, Microdata, and RDFa equivalently well. JSON-LD's advantage remains implementation ease and maintainability, not better AI parsing specifically — the underlying facts are what an AI engine actually cares about extracting correctly, regardless of which of the three formats happens to carry them on a given page.
Will Google eventually stop supporting Microdata and RDFa entirely?
There's no announced timeline for that, and both remain fully supported today. JSON-LD's advantage is practical ease of use, not that the alternatives are being phased out — though building anything new in JSON-LD going forward is still the sensible default regardless.
Want it implemented site-wide, in the right format, validated and ready to go? Scult's SEO team can handle the migration, the implementation, and the ongoing validation for you.
