Deploy agentsSIP overview

SIP Integration

Synthflow AI supports SIP (Session Initiation Protocol) integration for enterprise customers. This allows you to:

  • Bring your own VoIP provider (e.g. Twilio, Telnyx)
  • Use existing business phone numbers
  • Integrate with internal PBX systems (e.g. 3CX, Asterisk)
  • Maintain control over your call routing and infrastructure

This setup gives you full flexibility over your telephony stack while adding Synthflow’s conversational AI capabilities.

Supported Providers

Synthflow supports SIP trunking, a standard offered by most VoIP carriers and telephony providers. Commonly used and tested providers include:

  • Twilio
  • Telnyx
  • Vonage (SIP trunking plans)
  • RingCentral

To connect your phone numbers to Synthflow AI using Elastic SIP Trunking:

  1. Create a SIP trunk with your VoIP provider.
  2. Configure your phone numbers to route inbound calls through the trunk.
  3. Point the SIP trunk to Synthflow’s SIP server:
  4. Import your numbers into Synthflow AI and assign them to AI agents.

This setup allows Synthflow to answer inbound calls and optionally transfer calls back to your PBX or a live agent.

PBX Integration (Optional)

If you already use an on-prem or cloud-based PBX (e.g. 3CX, FreePBX, Asterisk):

  • You can configure a SIP trunk in your PBX to route specific calls to Synthflow AI.
  • This lets you use AI agents alongside your internal call flows and extensions.

Access & Rate Limits

SIP trunking support is available on the Enterprise plan only.
To enable this feature or request increased rate limits, please contact our sales team.