Inbound SIP

Subnets

Europe

• SIP DNS: eu.sip.callr.com
• SIP IP: 185.76.20.162/32 and 185.76.22.162/32
• RTP: 185.76.20.64/28 and 185.76.22.64/28

USA

• SIP DNS: usa.sip.callr.com
• SIP IP: 52.14.84.104/32
• RTP: 18.221.24.70/32 and 18.220.223.254/32

Number format

Phone numbers should always be E.164 prefixed by "+". An INVITE R-URI should look like this:

INVITE sip:[email protected] SIP/2.0

Outbound SIP

To make a call to a SIP endpoint, you can use dial@v1 in a Callr Actions scenario.

Here is an example dialing to OpenAI Realtime:

description: Dial to SIP

compat:
  version: "2025-09-01"

defaults:
  autoAnswer: false

branches:
  inbound-call:
    actions:
      - action: dial@v1
        params:
          targets:
            - number: sip:<project-id>@sip.api.openai.com;transport=tls
              timeout: 60