shipapis
StarSubmit an APISubmit API

Crossref Metadata Search vs Gutendex

Same instrument, two spec sheets — measured, not claimed.

APICrossref Metadata SearchNEW—GutendexNEW—
Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms——
P95 · ms——
Authnonenone
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useyesunclear
Data licenseOpen Crossref metadata (much is CC0)Public domain (Project Gutenberg data)
Free tierFree, no key (public pool)Free, no key
Rate limit5 requests/second, 1 concurrent (public pool, per X-Rate-Limit headers)Unpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

Crossref Metadata Search vs Gutendex: common questions

Which is more reliable, Crossref Metadata Search or Gutendex?

On our scheduled checks, Gutendex leads on measured uptime — Crossref Metadata Search at —% versus Gutendex at —% over 90 days. These are our own probe results, not provider claims; the uptime bars above show the day-by-day record for both.

Do Crossref Metadata Search and Gutendex need an API key?

Neither needs a paid key — Crossref Metadata Search is callable with no signup, and Gutendex is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call Crossref Metadata Search and Gutendex from the browser?

Yes — both Crossref Metadata Search and Gutendex send CORS headers over HTTPS, so front-end code can fetch either directly with no backend proxy. That makes them easy to swap in a client-side app while you compare responses.

Are Crossref Metadata Search and Gutendex free for commercial use?

Crossref Metadata Search allows commercial use on its free tier, and Gutendex has unclear commercial terms. We track service terms and the data license as separate fields — see the Commercial use and Data license rows above, and confirm both before shipping either in a paid product.