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PostStack vs Telnyx API

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

APIPostStackHEALTHY90Telnyx APIDEAD0
Uptime · 30d
Uptime · 90d100%60.6%
Uptime · 30d100%0.0%
P50 · ms318172
P95 · ms1890545
AuthapiKeyapiKey
CORSnoyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree tier — key may be requiredFree tier — API key required
Rate limitUnpublished50, 50;w=1 req/window · 49 remaining · resets 1
In directory since2026-07-052026-07-05
operationalpartialdownno data

PostStack vs Telnyx API: common questions

Which is more reliable, PostStack or Telnyx API?

On our scheduled checks, PostStack leads on measured uptime — PostStack at 100% versus Telnyx API at 60.6% 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, PostStack or Telnyx API?

Telnyx API has the lower median latency in our checks — PostStack responds in 318 ms versus Telnyx API at 172 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 PostStack and Telnyx API need an API key?

Both ask you to authenticate — PostStack uses an API key and Telnyx API 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 PostStack and Telnyx API from the browser?

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

Are PostStack and Telnyx API free for commercial use?

PostStack has unclear commercial terms, and Telnyx API 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.