Cisco Spark vs mailboxlayer

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

Uptime · 30d
Uptime · 90d100%100%
Uptime · 30d100%100%
P50 · ms1608316
P95 · ms29362634
AuthapiKeyapiKey
CORSyesno
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree tier — API key requiredFree tier — key may be required
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

Cisco Spark vs mailboxlayer: common questions

Which is more reliable, Cisco Spark or mailboxlayer?

Both are neck-and-neck — Cisco Spark and mailboxlayer each measure 100% uptime over 90 days on our probe schedule. Reliability here is verified from our own scheduled checks; use the 30-day bars above to see which has been steadier lately.

Which is faster, Cisco Spark or mailboxlayer?

mailboxlayer has the lower median latency in our checks — Cisco Spark responds in 1608 ms versus mailboxlayer at 316 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 Cisco Spark and mailboxlayer need an API key?

Both ask you to authenticate — Cisco Spark uses an API key and mailboxlayer uses an API key. Each key is free to obtain; the Auth and Card-required rows above spell out the signup terms.

Can I call Cisco Spark and mailboxlayer from the browser?

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

Are Cisco Spark and mailboxlayer free for commercial use?

Cisco Spark has unclear commercial terms, and mailboxlayer 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.