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Making and Receiving Calls

The Calling API allows businesses to make and receive voice calls (VoIP) via WhatsApp Cloud API.

What is Cloud API Calling?

Cloud API Calling enables businesses to handle voice calls (VoIP) on WhatsApp, in addition to messaging.

  • End-users initiate calls directly from the WhatsApp app.

  • Businesses manage signaling and call control via the Graph API.

  • Calling can be enabled or disabled anytime.

Limitations

  • Not recommended for businesses with no VoIP experience or no developer resources.

  • Supported: WebRTC and SIP.

  • Not supported: Routing to PSTN (mobile or landline) networks.

  • Setup is required per phone number.

Who can use it

To be eligible for the Calling API, businesses must:

  • Have a phone number with at least 1K business-initiated conversation limit.

  • Be using a number already on the Cloud API.

  • Have prior experience with SIP/WebRTC voice infrastructure.

360Dialog supports the API connection itself, but partners/clients are responsible for configuring and managing SIP/WebRTC — including call quality and routing.

Common Use Cases

How it works

Before configuring your number, it’s important to understand the basic architecture:

1

WhatsApp User taps the call button in the app.

2

Meta Signaling Infrastructure receives the event and triggers a webhook.

3

Meta RTC Infrastructure processes the call session.

4

Partner Signaling Infrastructure is notified of the incoming call.

5

Partner RTC/VoIP System receives and routes the call.

6

Business Agent answers the call through the VoIP system.

In this setup:

  • 360dialog provides the API endpoints to connect your number and signaling with Meta.

  • If there are issues in Meta’s RTC or signaling layers, we escalate directly to Meta.

  • While we don’t manage SIP/WebRTC infrastructure, we can provide guidance and escalate blockers if needed.

Customer Service Window

Besides setup, to place a call, a customer service window must be open. This can be opened using a template message.

The 24-hour window is also opened or refreshed when:

  • A user calls your business (even if unanswered).

  • A user answers a call initiated by your business.

Once active, the business can send free-form messages within the 24-hour window.

Pricing

With this, Calling API pricing differs by call type:

Call Type
Cost to Business
Details

User-initiated calls

Not charged

When a user calls your number via WhatsApp and you answer with the API, there is no cost.

Business-initiated calls

Charged

Based on: • Call duration, billed in 6s increments (rounded up) • Country code of the user’s phone number (rates vary).

Call Permission Request (CPR)

Charged (message rates)

Sent as a regular template message, following standard pricing rules (e.g., Marketing or Utility).

Country rates are available on the official rate card. Analytics and cost tracking will be available with the call_analytics endpoint in Meta's Documentation.

Practical Example: Calculating the Cost

Scenario: your business (in Brazil) calls a customer in Mexico. The call lasts 1 minute and 10 seconds (70 seconds), and it’s a business-initiated call.

Step-by-step cost calculation:

  1. Round up the duration Calls are charged in 6-second blocks. → 70 seconds ÷ 6 = 11.67 → rounded up to 12 blocks

  2. Apply the rate card Let’s assume the rate per block for calls to Mexico is $0.01 (for example only)

  3. Final cost → 12 × $0.01 = $0.12 USD

You can check real country rates on the official rate card.

What if the customer calls the business?

✅ In this case, there’s no cost for the business. However, the 24-hour service window is opened, allowing you to send messages without a template during that period

FAQs

Are messages charged separately during a call?

Yes. Messages exchanged during or around a call are charged separately and follow standard messaging rates based on their category (e.g., Marketing, Utility, etc.).

How is call duration calculated for billing?

Calls are charged in 6-second increments, always rounded up. For example, a call lasting 11.5 seconds will be charged as 12 seconds.

Does a voice call open a new 24-hour messaging window?

Yes. According to Meta’s documentation, when:

  • A user calls your business (even if not answered), or

  • A user answers your call,

→ A new 24-hour customer service window is opened for you to send standard Cloud API messages.

Can messaging and calling happen at the same time?

Yes. You can exchange messages with the end-user via the standard Cloud API while the voice call is ongoing.

What is the maximum number of concurrent calls allowed?

The limit is 1,000 concurrent calls per WhatsApp Business Account.

What happens if the calling rate limit is exceeded?

If the 1,000 concurrent call limit is exceeded:

  • The user trying to place a call will receive a generic error message (no specific audio or webhook is triggered).

  • Meta has indicated that this limit may be increased in the future, so the likelihood of hitting it is low.

Rate limits for messaging APIs and template creation/update are completely independent from calling limits.

You can find the official FAQ from Meta here: 🔗 https://developers.facebook.com/docs/whatsapp/cloud-api/calling/faq

Getting Started

How to Setup a Test Environment

Includes:

Using Session Initiation Protocol

Includes:

Inbound Calls

Includes:

Outbound Calls

Includes:

PreviousCreate order_details template message via APINextHow to Setup a Test Environment

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