Hi Team, I’m seeking clarification regarding Vapi’s concurrency limits. I recall reading that once a Twilio phone number is integrated with Vapi, the default concurrency limit (e.g., 10 simultaneous calls) no longer applies. However, I’m still observing this 10-call concurrency cap even after provisioning and using a Twilio number. Could you please help me understand how the concurrency limits work in this context — specifically, under what conditions (if any) they’re lifted or increased when using Twilio numbers?

**Vapi's concurrency limits remain in effect even when using Twilio numbers**—these limits are set by your Vapi plan, not by Twilio. To increase the number of simultaneous calls, you must upgrade your Vapi organization's concurrency limit in the [Vapi Dashboard](https://dashboard.vapi.ai/settings/billing). Example:

env
# To raise your concurrency, update your plan in the Vapi Dashboard
MAX_CONCURRENCY=20

Using Twilio does not remove or bypass these limits; queue management can help handle overflow, but does not increase the cap itself (according to documentation I have found). Source: - [Call queue management with Twilio](https://docs.vapi.ai/calls/call-queue-management)

I am already on Pay as you go plan but i don't see any option to specify concurrency limit

On the billing page of the Vapi dashboard, you can purchase additional concurrency lines. It's towards the middle of the page so you have to scroll down a little bit.