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?


Your Nexmo account can initiate voice calls at a limit of 30 requests per second for SIP and deprecated voice products. If you initiate voice calls at a faster rate that this, you will receive a threshold error and we will not queue the call. 

Current throughput on the Voice API endpoint:

  • 3 calls per second (including POST, and calls initiated by a NCCO e.g. Connect action)
  • 15 API requests per second for GET / PUT / DELETE

If your throughput exceeds this maximum you will be rate-limited and receive the HTTP response error code of 429. 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 from the local supplier or network. You can check the concurrency limit for your number in the below article:
Inbound Voice Restrictions, Features and Capacity

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