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Mempool vs OpenSea

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

APIMempoolNEW—OpenSeaNEW—
Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms——
P95 · ms——
AuthnoneapiKey
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverified (open-source project)Unverified
Free tierFree public API; no key for basic usageFree tier — API key required
Rate limitEnforced — HTTP 429 on excess, repeated abuse may be banned; numeric limits unpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

Mempool vs OpenSea: common questions

Which is more reliable, Mempool or OpenSea?

On our scheduled checks, OpenSea leads on measured uptime — Mempool at —% versus OpenSea 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 Mempool and OpenSea need an API key?

Mempool needs no key, while OpenSea requires a free API key. If you want to start calling without signup, reach for Mempool first.

Can I call Mempool and OpenSea from the browser?

Yes — both Mempool and OpenSea 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 Mempool and OpenSea free for commercial use?

Mempool has unclear commercial terms, and OpenSea 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.