Skip to main content

Rate Limits

Default Voice Rate Limits

The Bandwidth Voice API sets a default rate limit of 5 calls per second (CPS) and 100 active sessions.

The calls per second (CPS) rate limit is the number of inbound and outbound calls per second your account can process. If you think you may need additional voice capacity, please open a ticket with our Account Management team.

429 - Too Many Requests

If a rate limit is hit when creating an outbound call you will receive a 429 - Too Many Requests error.

You will also receive a message informing you of the reason for reaching this rate limit which can be:

  • Account call creation rate limit exceeded
  • Account concurrent call limit exceeded
429 Too Many Requests
'description': 'Account call creation rate limit exceeded',
'id': '',
'type': 'error'

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 the transferCompleteUrl also informing the reason in the errorMessage field.

Managing Calls

Bandwidth has introduced Outbound Call Queuing capabilities to help you manage your outbound call queue. This ensures your calls are not rejected if you exceed your calls per second (CPS) limits.

The amount of calls that can be in the outbound call queue is 5 minutes based on your provisioned CPS limit. For example, if your account is provisioned for 5 CPS, your queue capacity would be 5 CPS x 60 seconds x 5 minutes or 1500 calls.

For more information about rate limits and managing your queue, please visit the following: