SIP Webhooks and Prewarm

Burki exposes root-level SIP endpoints used by SIP carriers and the SIP bridge. These endpoints do not use the /api/v1 prefix.

https://api.burki.dev/sip-webhook
https://api.burki.dev/sip-status
https://api.burki.dev/sip-prewarm

The SIP bridge that terminates customer PBX/carrier traffic currently advertises:

SIP bridge IP: 52.21.157.171
SIP signaling: UDP/TCP 5060
SIP TLS: TCP 5061, if enabled
RTP media: UDP 10000-20000

PBX/carrier firewalls should allow 52.21.157.171 for both inbound calls to Burki and outbound calls from Burki. The HTTP endpoints above are backend/provider coordination endpoints; customer PBXs should send SIP traffic to the SIP bridge IP, not to /sip-webhook directly.

SIP Webhook

POST /sip-webhook

Receives SIP inbound call and provider event payloads. This endpoint is called by the SIP bridge/provider layer, not by normal application clients.

SIP Status

POST /sip-status

Receives SIP status callbacks for call lifecycle tracking.

SIP Prewarm

POST /sip-prewarm
Content-Type: application/json

The SIP bridge calls this endpoint before media streaming so Burki can prepare call context.

Request

{
  "call_sid": "sip-20260430-abc123",
  "from_number": "+15559876543",
  "to_number": "+15551234567",
  "outbound": false,
  "assistant_id": 123,
  "welcome_message": "Thanks for calling. How can I help?",
  "agenda": "Customer support intake",
  "variables": {
    "customer_id": "cust_123"
  }
}

Field	Type	Required	Description
`call_sid`	string	Yes	Burki/SIP call identifier used for the stream
`from_number`	string	No	Caller phone number
`to_number`	string	No	Destination or assistant phone number
`outbound`	boolean	No	Whether this is an outbound SIP call
`assistant_id`	integer	No	Assistant to prepare
`welcome_message`	string	No	Optional first assistant message
`agenda`	string	No	Optional call agenda/instructions
`variables`	object or JSON string	No	Runtime variables for the call

Response

{
  "call_sid": "sip-20260430-abc123",
  "prewarmed": true
}

Error Responses

400

{
  "error": "call_sid required"
}

Operational Notes

/sip-webhook and /sip-status are CSRF-exempt provider endpoints.
/sip-prewarm is intended for SIP bridge integrations before media streaming.
SIP bridge synchronization uses SIP_BRIDGE_URL and SIP_BRIDGE_API_KEY on the backend.
The bridge sync API receives org config at POST {SIP_BRIDGE_URL}/api/sync-organization.

API Documentation

Assistants

Assistant Phone Numbers

Assistant Documents (RAG)

Voice Cloning

Calls

Messaging

SIP Trunks

Billing

Phone Number Management

Call Data

Organization

Webhooks & System

Campaigns

WebSockets

Tools & Custom Actions

Conversation Flows

Learning & Memory

SIP Webhook

SIP Status

SIP Prewarm

Request

Response

Error Responses

Operational Notes

​SIP Webhook

​SIP Status

​SIP Prewarm

​Request

​Response

​Error Responses

​Operational Notes

SIP Webhook

SIP Status

SIP Prewarm

Request

Response

Error Responses

Operational Notes