Add Caption

Add Caption

curl --request POST \
  --url https://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang} \
  --header 'AccessKey: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "srclang": "<string>",
  "label": "<string>",
  "captionsFile": "<string>"
}
'

import requests

url = "https://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}"

payload = {
    "srclang": "<string>",
    "label": "<string>",
    "captionsFile": "<string>"
}
headers = {
    "AccessKey": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {AccessKey: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({srclang: '<string>', label: '<string>', captionsFile: '<string>'})
};

fetch('https://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}', 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://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}",
  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([
    'srclang' => '<string>',
    'label' => '<string>',
    'captionsFile' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "AccessKey: <api-key>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($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://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}"

	payload := strings.NewReader("{\n  \"srclang\": \"<string>\",\n  \"label\": \"<string>\",\n  \"captionsFile\": \"<string>\"\n}")

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

	req.Header.Add("AccessKey", "<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://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}")
  .header("AccessKey", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"srclang\": \"<string>\",\n  \"label\": \"<string>\",\n  \"captionsFile\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}")

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

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

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

{
  "success": true,
  "message": "<string>",
  "statusCode": 123,
  "data": {
    "valid": true,
    "errorList": [
      "<string>"
    ],
    "warningList": [
      "<string>"
    ],
    "warningMessage": "<string>"
  }
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123,
  "data": {
    "valid": true,
    "errorList": [
      "<string>"
    ],
    "warningList": [
      "<string>"
    ],
    "warningMessage": "<string>"
  }
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123
}

POST

library

{libraryId}

videos

{videoId}

captions

{srclang}

Add Caption

curl --request POST \
  --url https://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang} \
  --header 'AccessKey: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "srclang": "<string>",
  "label": "<string>",
  "captionsFile": "<string>"
}
'

import requests

url = "https://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}"

payload = {
    "srclang": "<string>",
    "label": "<string>",
    "captionsFile": "<string>"
}
headers = {
    "AccessKey": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {AccessKey: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({srclang: '<string>', label: '<string>', captionsFile: '<string>'})
};

fetch('https://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}', 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://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}",
  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([
    'srclang' => '<string>',
    'label' => '<string>',
    'captionsFile' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "AccessKey: <api-key>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($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://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}"

	payload := strings.NewReader("{\n  \"srclang\": \"<string>\",\n  \"label\": \"<string>\",\n  \"captionsFile\": \"<string>\"\n}")

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

	req.Header.Add("AccessKey", "<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://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}")
  .header("AccessKey", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"srclang\": \"<string>\",\n  \"label\": \"<string>\",\n  \"captionsFile\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang}")

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

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

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

{
  "success": true,
  "message": "<string>",
  "statusCode": 123,
  "data": {
    "valid": true,
    "errorList": [
      "<string>"
    ],
    "warningList": [
      "<string>"
    ],
    "warningMessage": "<string>"
  }
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123,
  "data": {
    "valid": true,
    "errorList": [
      "<string>"
    ],
    "warningList": [
      "<string>"
    ],
    "warningMessage": "<string>"
  }
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123
}

{
  "success": true,
  "message": "<string>",
  "statusCode": 123
}

Authorizations

AccessKey

string

header

required

AccessKey based authentication

Path Parameters

libraryId

integer<int64>

required

The ID of the video library.

videoId

string

required

The GUID of the video.

srclang

string

required

The srclang shortcode for the caption, e.g. "en".

Body

application/json

srclang

string | null

deprecated

Not used — the caption's srclang is taken from the srclang route segment instead. Any value sent here is ignored.

label

string | null

The text description label for the caption

captionsFile

string | null

Base64 encoded captions file

Response

The caption was successfully uploaded

success

boolean

Determines if the request was successful

message

string | null

Human-readable message describing the result, typically populated with error details when Success is false.

statusCode

integer<int32>

The HTTP status code corresponding to the result of the request.

data

object | null

The response payload. Some endpoints also populate this with error details when Success is false — see the endpoint's own response documentation.

Show child attributes

Last modified on September 10, 2026

API Reference

Core Platform API

Origin Errors API

CDN Logging API

Storage API

Stream API

Shield API

Edge Scripting API

Magic Containers API

Authorizations

Path Parameters

Body

Response