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 - it is a redirect that expires after ten minutes.

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