VAPI•6mo ago

3rd Party SIP for telephony

Hi Team,
We are attempting to register SIP through Vapi. I'm able to register the credentials on Zoiper and a SIP PBX however it fails with Vapi. Is there any way to add outbound proxy ?

I see traffic to the SIP server from Vapi servers however it gets rejected

comprehensive-tomato•7/22/25, 7:48 AM

DM let's discuss

comprehensive-tomato•7/22/25, 7:49 AM

afraid-moccasinOP•7/23/25, 5:36 AM

@Shubham Bajaj Could you assist please

KyleAPP•7/24/25, 7:31 AM

Hi DJ,

To use a third-party SIP provider with Vapi, you'll need to ensure that your setup adheres to Vapi's requirements and configuration process. Here's a brief guide to help you integrate your SIP provider:

Obtain Provider Details: Gather the SIP server address, and authentication credentials from your provider. Ensure you have at least one phone number (DID) from your provider.
Create a SIP Trunk Credential in Vapi: Use the Vapi API to create a new credential (type: byo-sip-trunkbyo-sip-trunk) using your SIP provider details. An example for creating a credential can be found here.
Associate Phone Number: Link your external phone number (DID) to the SIP trunk credential in Vapi by creating a Phone Number resource.
**Network Considerations**: Allowlist Vapi's IP addresses to ensure proper SIP traffic:
- 44.229.228.186/32
- 44.238.177.138/32
- 172.31.9.106/32
**Testing**: Initiate both outbound and inbound call tests to ensure calls are correctly handled.

Regarding your question about an outbound proxy, if your SIP provider requires specific network routing, consider specifying the required settings as part of your SIP trunk configuration with Vapi.

For comprehensive steps, you can refer to the SIP Trunking Guide that provides detailed instructions on setting up custom SIP trunks.

Ensure all configurations are set accurately as per your SIP provider's requirements, and check if there are additional settings necessary for your provider that Vapi supports, such as unique SIP domains or authentication methods.

SIP Trunking | Vapi

How to integrate your SIP provider with Vapi

afraid-moccasinOP•7/28/25, 3:30 AM

Failed

KyleAPP•7/30/25, 7:58 AM

Could you please provide some more information about how the setup failed?

3rd Party SIP for telephony

Similar Threads

Similar Threads

Similar Threads