Documentation

Rate limits

Limits that protect the platform and your accounts. Exceeding them returns 429 (or queues calls at your CPS rate).

Limits

Limit	Default	Scope	Notes
Calls per second (CPS)	1 (configurable)	Account	Outbound API calls beyond CPS are queued, not rejected.
Calls per minute	Configurable per account	Account	Fraud guardrail — adjustable in the dashboard.
Distinct destinations / hour	Configurable per account	Account	Fraud guardrail against destination fan-out.
PageSize	50, max 1000	Request	List endpoints.
TwiML length	4000 chars	Request	Inline `Twiml`.
Recording length	3600s default	Call	`maxLength` on `<Record>`.

Response headers

When you hit a rate limit, the response includes:

HTTP/1.1bash


HTTP/1.1 429 Too Many Requests
Retry-After: 30

Calls Per Second explained

CPS controls how fast outbound calls are initiated. Bursts above the limit are queued and executed at the CPS rate, so POST /Calls returns 201 immediately but the call may not start dialing until its turn. Increase CPS in the dashboard for higher throughput.

Best practices

Set generous PageSize to reduce request count.
Honor Retry-After on 429s.
Use waitFor in the SDK to poll a call instead of tight-looping.