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, with a maximum of 30 concurrent calls. If you initiate voice calls at a faster rate, you will receive a threshold error, and the call will not be queued.

Throughput for the Voice API is handled at a different rate:

  • 3 calls per second for outbound calls created using POST or Connect actions
  • 15 API requests per second for GET / PUT / DELETE

If your throughput exceeds this threshold, 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. There is also no concurrency limit for Voice API calls.

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

If you have a high call demand, please contact your Account Manager to ensure we serve your calls in the best way possible.

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