Twilio Voice API Limitation?

Question

Let's say I want to use Twilio for Voice (using the Say API), and I need to call 500 different phone numbers.

Looks like Twilio only supports 1 call or SMS per second and I found that information on this page: https://www.twilio.com/help/faq/twilio-basics/what-are-the-limits-on-outbound-calls-and-sms-messages-per-second

Assuming that I need to call and deliver something that is time-sensitive (say MFA code), does it mean the 500th user will get his/her call after 500 seconds as Twilio only processes 1 call or SMS per second?

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Say voice="woman" language="en">Your confirmation code is 3 4 6 7 8 9</Say>
</Response>

How does this work?

Is it possible for a Twilio Client to send 500 calls at the same time for 500 telephones?

Though it is highly unlikely that there will be a situation where I need to call 500 users at the same time, I would like to understand how many transactions Twilio can support.

I also see that I can contact Twilio Sales for higher limits. What is the maximum limit Twilio supports?

Answer 1

Twilio developer evangelist here.

You are absolutely right, Twilio will process one phone call/SMS message per second per phone number.

If you want to increase those limits, you can use more than one phone number to make calls/send messages. Given that, if you bought 500 numbers you would be able to make 500 calls at a time. However, buying 500 numbers is probably not part of your plan, which is why we ask you to contact sales if you do need more throughput. So that's what I'd advise you do right now if you think you need more.

As a tip, I'd recommend using voice="alice" in your <Say> block. It has a better voice and wider array of accents.