ClickSend REST API v3 vs Zipcodestack

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

Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms
P95 · ms
AuthapiKeyapiKey
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree tier — API key requiredFree tier — API key required
Rate limit6000 req/window · 5999 remaining · resets 1Unpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

ClickSend REST API v3 vs Zipcodestack: common questions

Which is more reliable, ClickSend REST API v3 or Zipcodestack?

On our scheduled checks, Zipcodestack leads on measured uptime — ClickSend REST API v3 at —% versus Zipcodestack 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 ClickSend REST API v3 and Zipcodestack need an API key?

Both ask you to authenticate — ClickSend REST API v3 uses an API key and Zipcodestack 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 ClickSend REST API v3 and Zipcodestack from the browser?

Yes — both ClickSend REST API v3 and Zipcodestack 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 ClickSend REST API v3 and Zipcodestack free for commercial use?

ClickSend REST API v3 has unclear commercial terms, and Zipcodestack 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.