# api key authentication: one X-Api-Key header - fastsaver api

one header, X-Api-Key. no oauth, no tokens to refresh, no sdk to install. the key lives in your console and you can rotate it any time.

> source: https://api.fastsaver.io/docs/authentication

## one header

Every billed request carries your key in a header. There is no OAuth, no bearer token to refresh, and no MCP server. If a tool tells you otherwise, it is wrong.

request

```
GET https://api.fastsaver.io/v1/fetch?url=…
X-Api-Key: fs_sk_…
```

### getting a key

Sign in at /auth with an email code, Google, or Telegram. New accounts start with 1,000 credits and no card. Your key is on the dashboard.

### the one exception

/balance needs the key but costs nothing and is deliberately kept out of your request log, so you can poll it. the `download_url` a youtube download returns needs no key either. open it right away: it expires after 5 minutes and opens at most 3 times.

warning: Anything called with your key is billed to you. If it leaks, regenerate it from the dashboard - the old key stops working immediately.