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ImprovMX API vs The SMS Works API

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

APIImprovMX APINEW—The SMS Works APINEW—
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 limit301 req/window · 300 remaining · resets 1783526520Unpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

ImprovMX API vs The SMS Works API: common questions

Which is more reliable, ImprovMX API or The SMS Works API?

On our scheduled checks, The SMS Works API leads on measured uptime — ImprovMX API at —% versus The SMS Works API 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 ImprovMX API and The SMS Works API need an API key?

Both ask you to authenticate — ImprovMX API uses an API key and The SMS Works 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 ImprovMX API and The SMS Works API from the browser?

Yes — both ImprovMX API and The SMS Works API 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 ImprovMX API and The SMS Works API free for commercial use?

ImprovMX API has unclear commercial terms, and The SMS Works 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.