Integration Patterns

Updated: Sep 16, 2026

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Possible high-level approaches

Approach	Number setup	Messaging partner responsibilities	Calling partner responsibilities	End business responsibilities
Messaging partner capable of calling	Extend an existing messaging number for calling, or use a new number.	Messaging partner reuses their app and subscribes it to calls webhooks. You can also create a new calling-specific app, but this is not recommended Process calls webhooks and coordinate with real-time media infra Make calling-related Graph API calls similar to messaging Graph API calls	Not applicable because there is only a single partner involved.	Enable and use calling Continue paying the partner, who now bills for calling usage
WhatsApp account model evolution (recommended)	A single number independently operated by a messaging partner and a calling partner, each with their own lines of credit.	Continue using the existing app and integration for messaging	Subscribe your app to calls webhooks Host Embedded Signup on your website so clients can share their existing WhatsApp account and phone number with you Process calls webhooks and coordinate with your real-time media infrastructure Make calling-related Graph API calls	Complete the calling partner’s Embedded Signup flow Share the existing WhatsApp account and phone number with the calling partner Keep the same phone number for messaging and calling
Exclusive calling partner	New number for calling	Not applicable because there is no messaging partner	Calling partner hosts Embedded Signup (ES) on their website pointing to their own app Onboard the business through their ES flow Meta bills the business directly unless the calling partner extends their credit line to the business The calling partner and business determine their own billing arrangement	Onboard using the calling partner’s ES flow Pay Meta directly unless the calling partner extends their credit line to you This requires a direct payment relationship with Meta. Setting up this relationship may take several weeks If the calling partner extends their credit line to you, pay the calling partner

Integrating using a third party calling provider detailed design

The following logical architecture illustrates how to integrate WhatsApp Business Calling using a third party (3p) calling provider.

In this scenario, you would use the 3p vendor internally, and that 3p vendor would not be visible to Meta. This pattern is similar to any other SaaS service you may be using.

The diagram also illustrates how this architecture can be optionally extended to integrate with the SIP infrastructure on your side.

Our terms disallow use of PSTN on any leg of the WhatsApp call in the overall call flow.

Even if you bridge WA call into the SIP world, you must ensure it still stays exclusively on VoIP and never touches the PSTN. SIP trunk by itself is not disallowed because technically a SIP trunk can be used without any PSTN at all.

Architecture diagram showing WhatsApp Business Calling integration with third-party provider

Single app vs. multiple apps

This section covers guidelines and considerations for reusing your existing messaging app for calling vs. creating a new app specifically for Calling API features.

To integrate with the WhatsApp Calling API, you need to call Graph API endpoints and process Webhooks from Meta. This requires you to have an app, and almost always, you should already have an app that is used for messaging.

You can reuse an existing app which is used for Embedded Signup and for a messaging use case.

In this setup, the Webhook Callback URI is the same for both message and call related webhooks, but the webhook payload can be used to distinguish between the two categories of functions (messaging and calling). Hence you can still forward Calling API specific webhooks to a calls related component from your main webhook business logic.

Reusing the same app offers the following benefits:

Reduced operational overhead (for example, app review, ongoing maintenance)
Simplified footprint on Meta
Equality between the app used for Embedded Signup and the one used for invoking Graph APIs and receiving webhooks
There would be no impact to existing functionality by reusing that app for calling. You need to ensure the webhook server gracefully handles calls-related webhooks.

Having separate apps is still supported, see the Get Started FAQ for details.

Guidelines for media path integration

The WhatsApp Business Calling VoIP stack is designed to be compatible with WebRTC. However, to ensure smooth integration with the WhatsApp protocol, Meta restricts the supported functionalities. As a result, the following requirements and recommendations apply.

Mandatory requirements

If any mandatory requirement is unmet, the call will fail. This failure can occur either during the call signaling phase, leading to a rejected call, or during the media packet decoding phase.

Use only the supported codecs.
For Opus, set the media clock rate to 48 kHz.
For Opus, use a ptime of 20 ms.
Audio must use a single SSRC. The Meta relay server overwrites the SSRC of all business audio packets to a fixed SSRC before these packets reach the WA client. WA clients handle only one audio source from their peers. Using multiple SSRCs causes undefined behavior. This undefined behavior includes severe media corruption, audio glitches, and likely total media failure.
Set the DTMF clock rate to 8 kHz.

Recommendations

While the following aspects are not mandatory, they are recommended to achieve high call quality and reliability.

ICE Process
- Our VoIP stack is ICE-LITE, so it is recommended that partners’ VoIP stack is ICE-FULL. (RFC 5245 Section 2.7⁠)
- Partners’ VoIP stack should initiate the ICE process by sending STUN connectivity checks.
- Partners’ VoIP stack should assume the ICE CONTROLLING role, as Meta will only assume the CONTROLLED role.
- Use regular nomination instead of aggressive nomination. (RFC 5245 Section 8.1.1.2⁠)
- Wait for the ICE process to complete before nominating the candidate and starting DTLS.
- Do not switch the candidate in the middle of the call.
DTLS
- Use ECDH keys for the DTLS certificates to prevent packet fragmentation during transmission.
- A partner should act as a DTLS client. (RFC 6347 Section 4.2⁠)
Media
- WhatsApp might not always send the first RTP media packet. Your media server’s media egress should not wait for WhatsApp media ingress. If it does, there is a chance of deadlock where each side is waiting for the other to start media transmission.
Addressing Audio Clipping
- See Audio clipping for details.