> ## Documentation Index
> Fetch the complete documentation index at: https://api-docs.voicecheap.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Add subtitles to a YouTube video
> Render supplied SRT subtitles into a public YouTube video and save the result.
Render supplied SRT subtitles into a public YouTube video and save the result.
```http theme={null}
POST https://api.voicecheap.ai/v1/actions/subtitles_burn_youtube
```
## Authentication and permissions
Send a VoiceCheap API key in this header. Authorization: Bearer with the same API key is also supported. OAuth access tokens are accepted only by
MCP, not by this REST endpoint.
Required permissions: `subtitles:write`.
An active paid subscription is required. Permissions do not change team roles, resource ownership, media credits, or plan limits.
## Parameters
Text value.
Maximum length: 2048. Format: "uri".
Optional at the transport boundary: the server injects an identifier before validation when omitted. Supply your own stable UUID v4 to recover safely from a lost response.
Format: "uuid". Pattern: `^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-4[0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$`.
Text value.
Minimum length: 1. Maximum length: 2097152.
Text value.
Minimum length: 2. Maximum length: 60.
JSON object. See the complete input schema for its nested fields.
JSON object. See the complete input schema for its nested fields.
The JSON Schema below preserves the exact field names, nested types, defaults, bounds, and accepted values exposed by discovery. Additional cross-field rules are listed in the operation notes.
```json theme={null}
{
"type": "object",
"properties": {
"youtubeUrl": {
"type": "string",
"maxLength": 2048,
"format": "uri"
},
"requestId": {
"description": "UUID v4 for this action. Reuse the same ID with identical arguments on retries.",
"type": "string",
"format": "uuid",
"pattern": "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-4[0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$"
},
"srtContent": {
"type": "string",
"minLength": 1,
"maxLength": 2097152
},
"detectedLanguage": {
"type": "string",
"minLength": 2,
"maxLength": 60
},
"subtitleLayout": {
"type": "object",
"properties": {
"maxLinesPerCaption": {
"anyOf": [
{
"type": "number",
"const": 1
},
{
"type": "number",
"const": 2
},
{
"type": "number",
"const": 3
}
]
},
"maxCharactersPerLine": {
"type": "integer",
"minimum": 24,
"maximum": 64
}
},
"required": ["maxLinesPerCaption", "maxCharactersPerLine"],
"additionalProperties": false
},
"subtitleStyle": {
"type": "object",
"properties": {
"fontFamily": {
"type": "string",
"enum": ["sans", "serif", "mono"]
},
"fontSize": {
"type": "string",
"enum": ["small", "medium", "large"]
},
"textColor": {
"type": "string",
"enum": ["white", "yellow", "cyan"]
},
"backgroundStyle": {
"type": "string",
"enum": ["outline", "box", "shadow"]
},
"position": {
"type": "string",
"enum": ["bottom", "middle"]
}
},
"required": ["fontFamily", "fontSize", "textColor", "backgroundStyle", "position"],
"additionalProperties": false
}
},
"required": ["youtubeUrl", "srtContent"],
"additionalProperties": false
}
```
## Idempotency
Use a UUID v4 in requestId or the Idempotency-Key HTTP header for each mutation. Reuse the same identifier and identical arguments after a network failure. If both are supplied, they must match. Replaying a saved request does not repeat the operation or charge another monthly call. Failed or interrupted requests are not restarted automatically.
Every mutation can return HTTP 202 when a retry finds the same request still running, even when its first execution is normally synchronous. If execution completed but resultStored is false, a retry returns HTTP 200 with saved request state instead of the original result. Retrieve the output through its domain history, result, or download action.
## Request examples
Replace example resource identifiers and media keys with values returned for your account. Keep the request identifier stable when retrying the same mutation.
```bash cURL theme={null}
curl --request POST 'https://api.voicecheap.ai/v1/actions/subtitles_burn_youtube' \
--header "x-api-key: $VOICECHEAP_API_KEY" \
--header 'Content-Type: application/json' \
--data '{"youtubeUrl":"https://www.youtube.com/watch?v=abcdefghijk","srtContent":"1\n00:00:00,000 --> 00:00:01,500\nHello world.\n","detectedLanguage":"english","subtitleLayout":{"maxLinesPerCaption":2,"maxCharactersPerLine":42},"subtitleStyle":{"fontFamily":"sans","fontSize":"medium","textColor":"white","backgroundStyle":"outline","position":"bottom"},"requestId":"13579bdf-2468-4ace-8bdf-0123456789ab"}'
```
```javascript JavaScript theme={null}
const input = {
youtubeUrl: 'https://www.youtube.com/watch?v=abcdefghijk',
srtContent: '1\n00:00:00,000 --> 00:00:01,500\nHello world.\n',
detectedLanguage: 'english',
subtitleLayout: {
maxLinesPerCaption: 2,
maxCharactersPerLine: 42,
},
subtitleStyle: {
fontFamily: 'sans',
fontSize: 'medium',
textColor: 'white',
backgroundStyle: 'outline',
position: 'bottom',
},
requestId: '13579bdf-2468-4ace-8bdf-0123456789ab',
};
const response = await fetch('https://api.voicecheap.ai/v1/actions/subtitles_burn_youtube', {
method: 'POST',
headers: {
'x-api-key': process.env.VOICECHEAP_API_KEY,
'Content-Type': 'application/json',
},
body: JSON.stringify(input),
});
const body = await response.json();
if (!response.ok) throw new Error(body.code + ': ' + body.message);
console.log(body);
```
```python Python theme={null}
import os
import requests
response = requests.post(
"https://api.voicecheap.ai/v1/actions/subtitles_burn_youtube",
headers={"x-api-key": os.environ["VOICECHEAP_API_KEY"]},
json={"youtubeUrl": "https://www.youtube.com/watch?v=abcdefghijk", "srtContent": "1\n00:00:00,000 --> 00:00:01,500\nHello world.\n", "detectedLanguage": "english", "subtitleLayout": {"maxLinesPerCaption": 2, "maxCharactersPerLine": 42}, "subtitleStyle": {"fontFamily": "sans", "fontSize": "medium", "textColor": "white", "backgroundStyle": "outline", "position": "bottom"}, "requestId": "13579bdf-2468-4ace-8bdf-0123456789ab"},
timeout=120,
)
body = response.json()
if not response.ok:
raise RuntimeError(f"{body.get('code')}: {body.get('message')}")
print(body)
```
## Response
This operation returns HTTP 202 while running. Save requestId and poll action\_request\_get with that identifier and the original operation name. Polling states are running, completed, failed, and interrupted. A completed result can point to a separate media job; continue with the operation-specific status or output action.
A saved YouTube subtitle-render result reference. Complete JSON contains srt, sourceSrt, subtitledVideoUrl and optional detectedLanguage.
```json HTTP 202 theme={null}
{
"data": {
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab",
"status": "running",
"pollAction": "action_request_get",
"pollAfterSeconds": 5
},
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab"
}
```
```json HTTP 200 theme={null}
{
"data": {
"resultId": "b3caf96f-5f2a-4619-832c-a12c0d57f78b",
"operation": "subtitles_burn_youtube",
"createdAt": 1792152000000,
"fileName": "voicecheap-subtitles_burn_youtube-b3caf96f-5f2a-4619-832c-a12c0d57f78b.json",
"byteLength": 225,
"contentType": "application/json; charset=utf-8",
"status": "completed",
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab",
"getAction": "subtitles_result_get",
"downloadAction": "subtitles_result_download",
"listAction": "subtitles_result_list"
},
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab"
}
```
```json HTTP 202 replay_running theme={null}
{
"data": {
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab",
"operation": "subtitles_burn_youtube",
"createdAt": 1792144800000,
"updatedAt": 1792144820000,
"status": "running",
"pollAfterSeconds": 5
},
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab"
}
```
```json HTTP 200 replay_completed_without_result theme={null}
{
"data": {
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab",
"operation": "subtitles_burn_youtube",
"createdAt": 1792144800000,
"updatedAt": 1792144820000,
"status": "completed",
"resultStored": false,
"message": "The action completed. Retrieve its output from the corresponding history or resource action."
},
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab"
}
```
## Result fields
| Field | Description |
| - | - |
| `data.resultId` | Owned saved-output UUID. Use it with getAction or downloadAction; it is distinct from requestId and any historyId. |
| `data.operation` | Generation action that produced this saved JSON. |
| `data.createdAt` | Unix timestamp in milliseconds when the saved output was prepared. |
| `data.fileName` | Suggested filename for a JSON export. |
| `data.byteLength` | UTF-8 bytes of the complete serialized output, not the compact metadata. |
| `data.contentType` | application/json; charset=utf-8. |
| `data.status` | completed on successful generation. Result history can also expose pending recovery entries. |
| `data.requestId` | Original action request UUID when recorded. |
| `data.getAction` | Owned retrieval action; includeContent defaults to false and must be true for complete structured output. |
| `data.downloadAction` | Authenticated export action returning full JSON as a content string. |
| `data.listAction` | Owned saved-output listing action for this permission domain. |
## Recover and poll this request
Use the same identifier even after a lost connection. If resultStored is false, retrieve the output through the corresponding history, result, or download action. Never start a second generation merely to check progress.
```bash theme={null}
curl --request POST 'https://api.voicecheap.ai/v1/actions/action_request_get' \
--header "x-api-key: $VOICECHEAP_API_KEY" \
--header 'Content-Type: application/json' \
--data '{"requestId":"13579bdf-2468-4ace-8bdf-0123456789ab","operation":"subtitles_burn_youtube"}'
```
```json HTTP 200 theme={null}
{
"data": {
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab",
"operation": "subtitles_burn_youtube",
"status": "completed",
"createdAt": 1792144800000,
"updatedAt": 1792144820000,
"resultStored": true,
"result": {
"resultId": "b3caf96f-5f2a-4619-832c-a12c0d57f78b",
"operation": "subtitles_burn_youtube",
"createdAt": 1792152000000,
"fileName": "voicecheap-subtitles_burn_youtube-b3caf96f-5f2a-4619-832c-a12c0d57f78b.json",
"byteLength": 225,
"contentType": "application/json; charset=utf-8",
"status": "completed",
"requestId": "13579bdf-2468-4ace-8bdf-0123456789ab",
"getAction": "subtitles_result_get",
"downloadAction": "subtitles_result_download",
"listAction": "subtitles_result_list"
}
}
}
```
## Operation notes
* Requires a paid subscription and the action permission. The actor's personal tool plan is rechecked at execution; saved tools and upload references belong to that actor, including when the credential is associated with a team.
* A successful action uses one shared monthly API/MCP call. Beginner allows 500, Starter 5,000 and Creator 25,000 calls/month; Pro, Scale and Enterprise have no monthly ceiling. Per-minute limits still apply: 30, 60, 120, 180, 300 and 600 respectively. Tool generation allowances are separate.
* Use a UUID v4 requestId, or an identical Idempotency-Key header, and retain the same action, ID and arguments on retries. A cached replay does not use another monthly call.
* This is an asynchronous action. The initial transport result is a running request with pollAction; poll action\_request\_get with this operation and the original requestId. The completed operation result shown here is a compact saved-output reference, not the generated body.
* Complete output is saved under authenticated ownership in encrypted storage independently of the bounded action polling cache. Call the returned getAction with resultId and includeContent: true for structured JSON, or downloadAction with resultId for JSON text. listAction provides a recovery route when only the original request is known.
* The saved JSON is limited to 32 MiB. Metadata never exposes its storage encryption key or an unauthenticated transcript download URL.
* Successful generation settles one personal tool allowance. Failed generation normally releases its tool reservation. When output persistence is uncertain, inspect the same request and saved-result history before generating again; the server retains the reservation to prevent duplicate usage.
* Higher plans without a monthly integration ceiling still have the tool-specific daily allowances and media limits below. These standalone actions use their tool allowance rather than dubbing minutes or TTS characters.
* Supply a public HTTPS YouTube video URL and valid SRT in srtContent. Although the action schema marks srtContent optional, the current YouTube renderer unconditionally validates it and returns 400 SRT\_EMPTY when omitted. This handler does not automatically generate YouTube subtitles.
* The imported YouTube video must be no longer than 2 hours and the assembled file must be no larger than 300 MiB. Import resolution follows the actor plan.
* Daily allowance per tool: Beginner 5, Starter 15, Creator 30, Pro 60, Scale 100 and Enterprise 100 successful generations. It is shared with the corresponding web tool and uses the account tool reset window.
* Shares the add-subtitles daily allowance with subtitles\_burn. One rendering uses one generation even when SRT was supplied.
* No previously uploaded fileKey is used. The rendered video is stored separately; its saved subtitle-burn history can refresh the temporary download URL.
## Usage
Each successful invocation consumes one monthly API/MCP call. Media credits and the operation's own generation allowances also apply.
## Errors
| HTTP status | Code | Meaning or recovery |
| - | - | - |
| 400 | `CREDENTIAL_IN_QUERY` | Credentials were supplied in an access\_token or api\_key query parameter. Send credentials in headers. |
| 400 | `DURATION_TOO_LONG` | The YouTube video exceeds 7,200 seconds. |
| 400 | `DURATION_UNKNOWN` | A positive YouTube video duration could not be determined. |
| 400 | `FILE_TOO_LARGE` | The assembled YouTube source exceeds 300 MiB. |
| 400 | `IDEMPOTENCY_CONFLICT` | The header and body request IDs differ. |
| 400 | `INVALID_REQUEST_ID` | requestId or Idempotency-Key is not a UUID v4. |
| 400 | `INVALID_SRT_CONTENT` | Supplied SRT contains no valid timed cue. |
| 400 | `INVALID_YOUTUBE_URL` | The HTTPS YouTube URL does not identify a supported video. |
| 400 | `SRT_EMPTY` | Supplied SRT is missing or empty; the current handler requires supplied subtitle content. |
| 400 | `VALIDATION_ERROR` | Arguments do not satisfy the action schema, or an unknown argument was supplied. |
| 400 | `VIDEO_AGE_RESTRICTED` | The YouTube video is age restricted. |
| 400 | `VIDEO_PRIVATE` | The YouTube video is private. |
| 400 | `VIDEO_REGION_BLOCKED` | The YouTube video is blocked for the server region. |
| 400 | `VIDEO_UNAVAILABLE` | The YouTube video is unavailable. |
| 401 | `API_KEY_EXPIRED` | The API key has expired. |
| 401 | `INVALID_API_KEY` | Provide a valid, unexpired API key. |
| 401 | `INVALID_CREDENTIAL` | The Authorization header is malformed or conflicts with x-api-key. |
| 401 | `MISSING_CREDENTIAL` | No usable header credential was supplied, or it exceeded 4096 characters. |
| 401 | `USER_NOT_FOUND` | The credential's account no longer exists. |
| 403 | `ACCOUNT_UNAVAILABLE` | The acting or billing account is unavailable or being deleted. |
| 403 | `AMBIGUOUS_TEAM_API_KEY` | The credential's user belongs to more than one team, so the billing context is ambiguous. |
| 403 | `INSUFFICIENT_SCOPE` | The API key or MCP connection lacks the required action permission. |
| 403 | `INTEGRATION_PLAN_UNSUPPORTED` | The account's integration limits could not be verified. |
| 403 | `PAID_SUBSCRIPTION_REQUIRED` | The authenticated actor no longer has a paid subscription when this tool action executes. |
| 403 | `SUBSCRIPTION_REQUIRED` | Use an active paid subscription. |
| 403 | `TEAM_OWNER_NOT_FOUND` | The effective team owner account could not be found. |
| 409 | `CONCURRENT_ACTION_LIMIT_REACHED` | This account already has 10 integration actions running. Poll an existing request before starting another. |
| 409 | `IDEMPOTENCY_CONFLICT` | Reuse an identifier only with the same operation and arguments. |
| 410 | `TOOL_RESULT_ACCOUNT_UNAVAILABLE` | The actor account is being deleted or no longer exists, so a durable result cannot be saved. |
| 413 | `TOOL_RESULT_TOO_LARGE` | Complete generated JSON exceeds 32 MiB and cannot be saved as an integration result. |
| 429 | `ADD_SUBTITLES_TOOL_DAILY_LIMIT_REACHED` | The shared uploaded/YouTube subtitle-render allowance is exhausted. |
| 429 | `INTEGRATION_MONTHLY_LIMIT_REACHED` | Used and pending calls have reached the shared monthly API/MCP allowance. |
| 429 | `INTEGRATION_RATE_LIMIT_REACHED` | The account has reached its per-minute integration limit; inspect retryAfterSeconds. |
| 500 | `INTERNAL_ERROR` | The original tool or result persistence failed internally. Inspect the saved request and output history before retrying a generation. |
| 502 | `INTERNAL_ERROR` | Generation or output saving failed. Check the original request and saved-result history before starting another generation. |
| 503 | `ACTION_RESULT_UNAVAILABLE` | The action ran but request-result persistence could not be confirmed. Poll the same action and requestId and inspect resource history before starting another write. |
| 503 | `INTERNAL_ERROR` | The generation or saved-result persistence outcome is uncertain or temporarily unavailable; use authenticated result recovery before generating again. |
| 503 | `SERVER_RESTARTING` | The server is restarting. Retry shortly and keep the same request identifier for a mutation. |
```json theme={null}
{
"code": "INSUFFICIENT_SCOPE",
"message": "This credential does not permit the requested action.",
"status": 403,
"details": {
"requiredScopes": ["subtitles:write"]
}
}
```
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