I'm using Nexmo/Vonage for sending SMS, Nexmo allows 30 concurrent requests for the operations, and for sending messages it allows 1 SMS/Sec for long code and 30mps (message per second) for the toll-free numbers.
right now I'm using it at its full capacity by buying multiple numbers, I just want to know how I can manage to increase its capacity for sending?
and one more thing as it has 30 concurrent requests when I buy numbers in bulk while sending it generates an error of request exceed.
I want to send around 5 million messages in a day.
There's a few things that go into the actual number of messages you can send per day.
The first is the throughput you listed above. Those are general limits that, by default, apply to all accounts and then the country they are sending in. So as you mentioned 1/sec or 30/sec depending on the number type. 30/sec is also our API limit, so you will need to contact [email protected] to get that raised if you want to send more than 30/sec no matter what.
For US traffic you will also need to register any Application-To-Person SMS traffic (A2P Traffic) with the carriers ahead of time through what is known as 10DLC. This is a carrier-imposed system that further dictates what and how many SMS messages you can send. From your Customer Dashboard you will need to register the brand you are sending as, and register a campaign. This will tell you the limits that each carrier will allow. Each carrier (T-Mobile and AT&T for the moment, Verizon will be joining in the future) will have their own limits even outside of our limits.
10DLC limits vary by use case, carrier, and how trustworthy the carriers think a brand is.
I would start the 10DLC process now to get an idea of the limits you will be constrained by the carriers, and from there you'll have a better idea of what you'll need to do either in API increases or moving to something like a dedicated short code.