What is the maximum number of calls per second?


  • How many outbound calls can I make at the same time?
  • What is the maximum number of simultaneous calls you support?
  • What is Nexmo's outbound voice channel capacity?
  • How many calls can I make simultaneously?
  • What is the throughput for Voice API requests?
  • What is the limit for concurrent outbound voice calls?


Maximum throughput for our outbound SIP trunking service is 30 calls per second. If you initiate SIP calls at a faster rate, you will receive a threshold error, and the call will not be queued. You would need to lower your call initiation rate and retry the rejected call.

Maximum throughput for the Voice API is handled as follows:

  • 3 HTTP POST API requests or Connect actions per second (creating outbound calls) 
  • 15 HTTP GET / PUT / DELETE API requests per second 

If your throughput exceeds this threshold, you will receive the HTTP response error code of 429, and your request will not be queued. You would need to lower your sending rate and retry the request.

Virtual numbers may have their own independent concurrent capacity, depending on the limitations of the local supplier or network. You can check the concurrency limit for your number in the below article:
Inbound Voice Restrictions, Features and Capacity

If you have a business need for higher call throughputs, please contact your Account Manager to ensure we serve your needs in the best way possible.

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