01
One-sentence definition
Add a machine-readable instruction layer to page content.
02
What problem it addresses
It can reduce ambiguity in entity recognition and support search understanding, but it cannot replace visible, useful content.
03
Fit and non-fit
Good fit
- Sites with clear entities, attributes and relationships
- Content that needs machines to identify page types and key fields consistently
Not a fit
- Pages whose facts are incomplete or conflict with markup
- Projects treating markup as a ranking shortcut
04
Prerequisites
Accessible pages with visible, truthful content
A supported type and required fields
Coordination across development, content and monitoring
05
Inputs and outputs
| Inputs | Outputs |
|---|---|
| Page-type and entity definitions | JSON-LD or another supported format |
| Visible page facts | Field-to-content consistency checks |
| Official field requirements and validation results | Error, warning and update log |
06
Standard steps
Organization and Article markup
FAQ, Breadcrumb and DefinedTerm markup
Validation errors and update dates
07
Decision criteria
Match the visible page content
Use an appropriate schema type
Validate before launch and maintain over time
08
Common failure modes
Adding markup automatically improves ranking
Markup may describe information that is not visible on the page
09
Metrics
Valid item ratio
Share of markup recognized without critical errors.
Field consistency
Consistency between markup and visible page content.
Maintenance timeliness
Speed of markup updates after page changes.
10
Case anatomy
Align fields before writing markup
Context
The same product used different names and price conventions across page, database and structured data.
Approach
Canonical fields and data sources were established before the page and JSON-LD consumed the same values.
Key lesson
The hard part of structured data is often data governance, not syntax.
11
Tools and templates
12
Revision history
Version 2.0
2026-07-15
Upgraded to a deep knowledge unit with fit boundaries, inputs and outputs, metrics, a case and claim-level evidence.
Related terms
Evidence and sources
Google Search Central
2026-07-15
Google Search Essentials
This source supports: Crawling, content quality, spam policies and foundational SEO boundaries.
Google Search Central
2026-07-15
Introduction to structured data
This source supports: Structured data helps machines understand entities and properties but does not guarantee search presentation.