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POST
Send a WebRTC offer

Authorizations

Authorization
string
header
required

An API key from Settings → API keys, sent as Authorization: Bearer kb_live_…. A workspace key starts kb_; a personal key starts kbp_ and acts as its owner.

Headers

X-Webcall-Grant
string | null
Idempotency-Key
string
required

A unique key (a UUID works) for this request. Retrying with the same key returns the first answer instead of running twice.

Maximum string length: 255
Kallabot-Version
enum<string>

The API version to answer as, a date (YYYY-MM-DD). Leave it out for the current version (2026-11-07). An unknown version is refused with 400 unsupported_api_version.

Available options:
2026-11-07
Example:

"2026-11-07"

Path Parameters

call_id
string
required

Body

application/json

Small WebRTC transport session arguments for the runner.

Parameters: sdp: The SDP string (Session Description Protocol). type: The type of the SDP, either "offer" or "answer". pc_id: Optional identifier for the peer connection. restart_pc: Optional whether to restart the peer connection. request_data: Optional custom data sent by the customer.

sdp
string
required
type
string
required
pc_id
string | null
restart_pc
boolean | null
request_data
unknown

Response

Successful Response

sdp
string
required

The SDP answer.

type
string
required

Always answer.

pc_id
string | null

The peer connection's id; send it with ICE candidates.