Skip to main content

Rate Limits and Call Queues

Rate limits for the Voice API are set by account by your customer account manager. By default, rate limits are set to 3 CPS and 30 active sessions. If you think you may need additional voice capacity, please open a ticket with our Account Management team.

If a rate limit is hit when creating an outbound call the API will return a HTTP-429 informing the reason with the message Account call creation rate limit exceeded or Account concurrent call limit exceeded.

If a rate limit is hit during a <Forward>, the call will be allowed, but will still count against the limit, so subsequent calls may be rate limited.

If a rate limit is hit during a <Transfer>, the error will be sent to transferCompleteUrl also informing the reason in the errorMessage field.

As an alternative to hard rate limiting for outbound calls, you may have your account manager enable outbound call queueing. Your queue size is limited to a maximum of 5 minutes worth of outbound calls at your dequeing rate. More details on queueing calls can be found in the calls api documentation

There are no notifications when inbound calls are rejected due to rate limits.