Public HTTPS endpoint and events (balance.low with balance_threshold_usd, job.finished). The signing secret is returned only when the webhook is first created.

Needs an API key with the write scope settings:write. Write scopes are off by default and only the account owner can grant them, signed in to the console. Every change made with a key shows up in the console's notifications. Not charged; counted in the same 60 requests per minute per account.