Append Avatar Realtime Text

Append a text delta to a session created with type: text_stream. Send fragments as they become available (e.g. tokens streamed from an upstream LLM); the avatar speaks them in order. Set final: true on the last delta to close input — further appends to a closed stream return 410. Returns the total bytes buffered so far.

POST /v3/avatar-realtime/{stream_id}/text

Append Avatar Realtime Text

cURL

curl --request POST \
  --url https://api.heygen.com/v3/avatar-realtime/{stream_id}/text \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "delta": "<string>",
  "final": false
}
'

202

{
  "data": {
    "buffered_bytes": 123,
    "ok": true
  }
}

Authorizations

ApiKeyAuthBearerAuth

x-api-key · string · header · required

HeyGen API key. Obtain from your HeyGen dashboard.

Path Parameters

stream_id · string · required

Streaming session identifier returned by POST /v3/avatar-realtime.

Body

application/json

Append one text delta to a streaming session created with type='text_stream'.

delta · string · required

Text fragment to append. May be a single token or a coalesced batch of tokens. Must be non-empty unless final: true (which allows an empty delta to close the stream).

final · boolean · default: false

If true, this is the last delta — input is closed after this request. Further POSTs to this stream return 410.

Response

202

application/json

Accepted — submission acknowledged; poll for completion.

data · AppendTextDeltaResponse · object

Response data for POST /v3/avatar-realtime/{stream_id}/text.

Show child attributes