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VCPaaS & OTP APIsFull list
APIs for SMS, voice, WhatsApp and one-time codes in your app.
4 tools1 with a free plan4 with an API
Subcategories · 8CPaaS & OTP APIs
4 tools
VV
Free trial
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Voice, video, messaging and verification APIs for developers and businesses
CPaaS & OTP APIsAPI
P
PP
Free trial
P
Voice AI agents and carrier-grade telephony APIs for businesses and developers
AI voice agents & IVRAPI
S
SS
Free trial
S
Messaging, voice, email and verification APIs for businesses and developers
CPaaS & OTP APIsAPI
T
TT
Freemium
T
Phone number lookup API for validation, line type and fraud signals
Number lookup & HLRFree planAPI
How to choose cpaas & otp apis tools
Most CPaaS providers can send an SMS. What really separates them is coverage, pricing model and how much you need beyond basic messaging.
- Channel breadth. Decide which channels you need now and which you'll need later. Vonage covers voice, video, messaging and verification. Sinch adds email alongside messaging, voice and verification. Plivo is built around voice, including voice AI agents and carrier-grade telephony.
- Verification vs. validation. Sending one-time codes is a different job from checking a number before you send to it. Twilio Lookup handles the second part: it validates numbers and returns line type and fraud signals. It works well next to an OTP sender.
- Pricing model. Sinch, Plivo and Vonage offer free trials. Twilio Lookup is freemium. Compare per-message and per-lookup rates for the countries you'll actually send to.
- Platform and SDK support. All four are API-first. Vonage also lists iOS and Android, which helps if you're building in-app calling or video.
Frequently asked questions
Are there free CPaaS or OTP APIs?
Twilio Lookup has a freemium plan. Sinch, Plivo and Vonage offer free trials, so you can test before you pay. Expect usage-based charges once you go to production.
How much do these APIs cost?
Prices depend on usage, channel and destination country. We don't list exact rates. Check each provider's pricing page for the countries you plan to reach.
What should I look for in an OTP or messaging API?
Check which channels you need (SMS, voice, WhatsApp, email), whether it offers built-in verification, and whether it covers your target countries. Also check SDK support. Number validation, as with Twilio Lookup, can cut failed sends and fraud.
What are the alternatives to Twilio?
Here we list Sinch (messaging, voice, email, verification), Vonage (voice, video, messaging, verification) and Plivo (voice-focused telephony and voice AI agents). Twilio Lookup is the Twilio tool listed here, and it covers number validation.