Onyx Bazaar vs Open Library

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

Uptime · 30d
Uptime · 90d100%88.2%
Uptime · 30d100%81.7%
P50 · ms6071629
P95 · ms13894878
Authnonenone
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedMixed — mostly open
Free tierFree — limits not publishedUnlimited within courtesy limits
Rate limitUnpublishedSoft — identified UA appreciated
In directory since2026-07-052026-05-02
operationalpartialdownno data

Onyx Bazaar vs Open Library: common questions

Which is more reliable, Onyx Bazaar or Open Library?

On our scheduled checks, Onyx Bazaar leads on measured uptime — Onyx Bazaar at 100% versus Open Library at 88.2% 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, Onyx Bazaar or Open Library?

Onyx Bazaar has the lower median latency in our checks — Onyx Bazaar responds in 607 ms versus Open Library at 1629 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 Onyx Bazaar and Open Library need an API key?

Neither needs a paid key — Onyx Bazaar is callable with no signup, and Open Library is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call Onyx Bazaar and Open Library from the browser?

Yes — both Onyx Bazaar and Open Library 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 Onyx Bazaar and Open Library free for commercial use?

Onyx Bazaar has unclear commercial terms, and Open Library 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.