Authentication
Authenticate API requests using Bearer tokens or X-API-Key, and understand rate limits.
All requests to the YouTube Transcript Platform API must be authenticated using a valid API key.
Authentication Headers
You can authenticate using either standard Bearer token or the X-API-Key header:
Authorization: Bearer YOUR_API_KEYOr alternatively:
X-API-Key: YOUR_API_KEYKeep your API key secret
Never expose your API key in client-side code, public repositories, or browser network requests. Use environment variables and server-side proxying.
Requests without a valid authorization token receive a 401 Unauthorized response with a standard error envelope:
{
"error": {
"code": "unauthorized",
"message": "missing or invalid authorization token",
"retryable": false
}
}Rate Limits & Concurrency
API keys have default rate limits based on your account tier:
| Tier | Rate Limit | Burst Capacity |
|---|---|---|
| Free (no pack bought) | 1 req/s, 100 requests per day (UTC) | 20 |
| Starter ($9) | 300 RPM (5 req/s) | 50 |
| Popular ($29) | 600 RPM (10 req/s) | 100 |
| Value ($79) | 3,000 RPM (50 req/s) | 300 |
| Custom / Dedicated | Above 3,000 RPM by written reservation | Dedicated capacity |
Rate limit exceeded?
When you exceed your rate limit, the API returns 429 Too Many Requests with X-RateLimit-Limit and a Retry-After header indicating seconds until reset. Free keys that use up the day's 100 requests get 429 with the code daily_limit_exceeded until 00:00 UTC; any credit pack removes the daily limit. See Credits & Errors for all error codes.