Move between them in the dashboard; charges prorate by the day.
The endpoint returns 429 quota_exceeded. There are no overages by design — you keep receiving the same response until you upgrade or until the period rolls over.
Yes. Plan changes take effect immediately; charges prorate by the day. Downgrades take effect at the next period.
Not in v1. Month-to-month is the only model — keeps the billing logic minimal.
Talk to us at hi@vipvap.com. We size plans around reasonable quantities of OTP emails; we don't take on >25k/month accounts that we'd have to refuse.