Errors and limits
Envelope
Every response — success or failure — looks like this:Status codes
Rate limits
Authentication endpoints are throttled per IP (20 requests/minute), with five failed password attempts locking sign-in for 15 minutes. Sending is paced by your plan’s per-minute rate and monthly allowance instead — see Billing.Validation
Bodies are validated strictly: unknown rules are rejected, emails must parse, and passwords need at least 12 characters. Themessage always explains the first problem; fix it and resend.