Crossref Metadata Search vs Kanji API

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

Uptime · 30d
Uptime · 90d97.1%100%
Uptime · 30d95.0%100%
P50 · ms522395
P95 · ms26832870
Authnonenone
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useyesunclear
Data licenseOpen Crossref metadata (much is CC0)Unverified
Free tierFree, no key (public pool)Free — limits not published
Rate limit5 requests/second, 1 concurrent (public pool, per X-Rate-Limit headers)Unpublished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 Kanji API: common questions

Which is more reliable, Crossref Metadata Search or Kanji API?

On our scheduled checks, Kanji API leads on measured uptime — Crossref Metadata Search at 97.1% versus Kanji API at 100% over 90 days. These are our own probe results, not provider claims; the uptime bars above show the day-by-day record for both.

Which is faster, Crossref Metadata Search or Kanji API?

Kanji API has the lower median latency in our checks — Crossref Metadata Search responds in 522 ms versus Kanji API at 395 ms (P50). Tail latency (P95) is in the table above; for most workloads the median is the number that shapes how the API feels.

Do Crossref Metadata Search and Kanji API need an API key?

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

Can I call Crossref Metadata Search and Kanji API from the browser?

Yes — both Crossref Metadata Search and Kanji API 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 Kanji API free for commercial use?

Crossref Metadata Search allows commercial use on its free tier, and Kanji API 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.