Synthesia API uses API keys as an authentication mechanism.

You will find your API key in Synthesia STUDIO account settings.

If you cannot find your API key, please follow the Get Started with Synthesia API guide.

The API key should be passed as a header value on each request:

curl "https://api.synthesia.io/v2/videos" \
  -H "Authorization: ${API_KEY}" \
  -X GET