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Phone Numbers ​

Buy or port in a real phone number with the Zernio API, then turn on Calls, SMS and WhatsApp on that same number.

Buy a phone number with POST /v1/phone-numbers/purchase, or port one in, then turn on the features you need on that same number. A number is the unit of telephony on Zernio:

  • Calls (PSTN voice) are on by default on every number.
  • SMS (text and MMS) is enabled per number; it needs an SMS-capable number, plus a carrier registration in the US.
  • WhatsApp connects the number to a WhatsApp Business Account.

One number can do all 3 or only one. This section covers getting and managing the number; what you do with it lives in Voice & Calls, SMS and WhatsApp. There is no separate "WhatsApp number": a WhatsApp number is a phone number with WhatsApp enabled on it. The older WhatsApp-scoped number endpoints are deprecated aliases kept for existing integrations; new code uses /v1/phone-numbers.

Quick reference ​

PropertyValue
Countries57, plus 11 more by pre-order
Default countryUnited States
Price$3 to $30 per month per number, by country and number type
Calls (PSTN)Every number, on by default
SMSPer number, SMS-capable countries only
WhatsAppConnect the number to a WhatsApp Business Account
Get a numberPurchase from inventory, pre-order, or port one in
Number limitYour profile limit, and 50 where profiles are uncapped

Before you start ​

Telephony (numbers, voice, SMS) requires usage-based billing with a payment method on file. With that in place every country is available, numbers provision inline with no separate checkout, and each number bills per month on your usage-based invoice. Calls and SMS on a number meter on the same invoice.

The lifecycle ​

  1. See what is available. Availability and per-country pricing lists the countries, number types, per-country prices and which capabilities each supports.
  2. Get a number. Purchase one from inventory (it provisions in the same request, auto-assigned or the exact number you pick) or port in a number you already own. Regulated countries need a one-time KYC form first, and when one is out of stock (or stocked nowhere) that same form pre-orders the number.
  3. Turn on features. Calls are already on. Enable SMS (US numbers need a carrier registration, see SMS) or connect WhatsApp (see WhatsApp).
  4. Use it. Place and receive calls (see Voice & Calls), send texts, and read one call history across every number and channel.

API conventions ​

  • A number is the unit; features are sub-resources on it. Enable or disable a capability with POST or DELETE on /v1/phone-numbers/{id}/{feature} (/{id}/voice, /{id}/sms). Activity lives on its own top-level resources: call history at /v1/calls, texts at /v1/sms/messages, outbound calls at /v1/voice/calls.
  • State-changing actions read as POST /resource/{id}/{verb}: POST /v1/voice/calls/{id}/end, /transfer, POST /v1/sms/registrations/{id}/verify-otp, /appeal.