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
}
'

import requests

url = "https://api.heygen.com/v3/avatar-realtime/{stream_id}/text"

payload = {
    "delta": "<string>",
    "final": False
}
headers = {
    "x-api-key": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {'x-api-key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({delta: '<string>', final: false})
};

fetch('https://api.heygen.com/v3/avatar-realtime/{stream_id}/text', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.heygen.com/v3/avatar-realtime/{stream_id}/text",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'delta' => '<string>',
    'final' => false
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "x-api-key: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.heygen.com/v3/avatar-realtime/{stream_id}/text"

	payload := strings.NewReader("{\n  \"delta\": \"<string>\",\n  \"final\": false\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("x-api-key", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.heygen.com/v3/avatar-realtime/{stream_id}/text")
  .header("x-api-key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"delta\": \"<string>\",\n  \"final\": false\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.heygen.com/v3/avatar-realtime/{stream_id}/text")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["x-api-key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"delta\": \"<string>\",\n  \"final\": false\n}"

response = http.request(request)
puts response.read_body

202

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

{
  "error": {
    "code": "invalid_parameter",
    "message": "'delta' must be non-empty unless final=true.",
    "param": "delta",
    "doc_url": null
  }
}

{
  "error": {
    "code": "authentication_failed",
    "message": "Invalid or expired API key. Verify your x-api-key header.",
    "param": null,
    "doc_url": null
  }
}

{
  "error": {
    "code": "invalid_parameter",
    "message": "Video not found",
    "param": "<string>",
    "doc_url": "<string>"
  }
}

{
  "error": {
    "code": "rate_limit_exceeded",
    "message": "Too many requests. Retry after the duration specified in the Retry-After header.",
    "param": null,
    "doc_url": null
  }
}

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.

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