PubMed E-utilities vs Vector Express v2.0

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

Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms
P95 · ms
Authnonenone
CORSyesno
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree — limits not publishedFree
Rate limit3 req/window · 1 remaining5 req/window · 4 remaining · resets 1783513379
In directory since2026-07-052026-07-05
operationalpartialdownno data

PubMed E-utilities vs Vector Express v2.0: common questions

Which is more reliable, PubMed E-utilities or Vector Express v2.0?

On our scheduled checks, Vector Express v2.0 leads on measured uptime — PubMed E-utilities at —% versus Vector Express v2.0 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 PubMed E-utilities and Vector Express v2.0 need an API key?

Neither needs a paid key — PubMed E-utilities is callable with no signup, and Vector Express v2.0 is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call PubMed E-utilities and Vector Express v2.0 from the browser?

Only PubMed E-utilities is browser-friendly — it returns CORS headers over HTTPS. Vector Express v2.0 needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are PubMed E-utilities and Vector Express v2.0 free for commercial use?

PubMed E-utilities has unclear commercial terms, and Vector Express v2.0 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.