Open Library vs Universities List

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

Uptime · 30d
Uptime · 90d88.2%100%
Uptime · 30d81.7%100%
P50 · ms1629510
P95 · ms48782076
Authnonenone
CORSyesyes
HTTPSyesno
Card requirednono
Commercial useunclearunclear
Data licenseMixed — mostly openUnverified
Free tierUnlimited within courtesy limitsFree — limits not published
Rate limitSoft — identified UA appreciatedUnpublished
In directory since2026-05-022026-07-05
operationalpartialdownno data

Open Library vs Universities List: common questions

Which is more reliable, Open Library or Universities List?

On our scheduled checks, Universities List leads on measured uptime — Open Library at 88.2% versus Universities List 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, Open Library or Universities List?

Universities List has the lower median latency in our checks — Open Library responds in 1629 ms versus Universities List at 510 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 Open Library and Universities List need an API key?

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

Can I call Open Library and Universities List from the browser?

Only Open Library is browser-friendly — it returns CORS headers over HTTPS. Universities List needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are Open Library and Universities List free for commercial use?

Open Library has unclear commercial terms, and Universities List 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.