First-Party Research · July 30, 2026
We Validated the Structured Data of 81 Marketing Agencies
Agencies sell technical SEO. How well do they implement the most technical part of it on their own homepages? We fetched every agency website curated across our published rankings and validated their JSON-LD — parse integrity, entity types, and graph coherence. Every number below is measured, dated, and reproducible.
10 of 72 reachable homepages had zero JSON-LD blocks in their served HTML.
Two agencies serve structured data that fails JSON.parse — invisible to every search engine, silently.
6 sites define the same @id more than once and 2 reference entities that are never defined.
Only 8 of 72 agencies mark up answers — the format AI search systems quote most readily.
What We Found
Of the 81 agency domains in our sample, 72 responded to a standard homepage request. 62 of those 72 (86%) serve at least one JSON-LD block — meaning 10 agencies (14%) present no machine-readable identity at all on the page that defines who they are. For businesses whose product includes entity SEO, that is the shoemaker's-children result we half expected and still found surprising at this rate.
More interesting than absence is broken presence. Two agencies ship JSON-LD that fails to parse — a stray character or template bug that silently voids every entity claim in the block. And among the 62 sites with valid JSON, 6 define the same @id more than once with different content, while 2 reference entity IDs that are never defined anywhere on the page. These are exactly the failure modes that never show up in paste-in validators, because they only appear when you look at the full served page.
On the positive side, 76% declare an Organization, LocalBusiness, or ProfessionalService entity, and 39% mark up breadcrumbs. But only 11% use FAQ schema — the markup that maps most directly onto how AI search systems retrieve and quote answers. If you want an edge that most of your competitors measurably do not have, this is it.
Schema Types Found Across the Sample
Number of agency homepages (of 62 with JSON-LD) declaring each type.
View as table
| Schema type | Sites declaring it |
|---|---|
| Organization | 45 |
| WebSite | 44 |
| ImageObject | 42 |
| WebPage | 36 |
| SearchAction | 35 |
| BreadcrumbList | 28 |
| PostalAddress | 24 |
| Person | 20 |
| ContactPoint | 14 |
| LocalBusiness | 12 |
| AggregateRating | 10 |
| FAQPage | 8 |
Methodology
- Sample: every external agency website curated across our published /best rankings — 81 unique domains. This is a curated sample of real, verified agencies, not a random sample of all agencies; read the percentages accordingly.
- Collection: one GET request per homepage on July 30, 2026, 15-second timeout, no retries, an identified research user-agent. 72 of 81 responded with HTTP < 400; unreachable sites (bot walls, timeouts) are excluded from all percentages.
- Analysis: the same engine as our free schema validator — JSON-LD extraction from served HTML, JSON parsing, entity-type inventory, duplicate-@id and dangling-reference detection. Client-side-injected schema is not visible to this method, and we say so wherever it matters.
- Reporting: aggregates only. We do not name individual agencies’ defects; several are firms we rank favorably on other merits.
- Reproducibility: run any homepage through our free validator and you will see exactly what this study saw for that site.
Validate your own site with the same engine: free schema validator. Raw aggregate data is versioned in our repository with the collection script.
Is Your Entity Graph in the Broken 13%?
Check in thirty seconds with the validator this study was built on — then talk to us if you'd rather have it fixed than diagnosed.