When to use MailChimp Single or Batch Operations?

Question

Sorry if this is a repeating Question. But I'm bit confused when to use MailChimp Single or Batch Operations?

I want to build a simple PHP script to Subscribe a User to MailChimp List. That is triggered every time a Payment Provider pings the PHP script.

But what would be the safest MailChimp Monkey Way of doing this with MailChimp API V3.0?

1. Do run Subscribe on every new Order Ping .
2. Or do I add them to a list and batch Subscribe them every 5 min

Answer 1

I guess should have answered my own Question : There is no one prefect solution.

Number "1." is possible on low frequency but keep in mind that MailChimp has limit of 10 simultaneous connections.

Once you start receiving "429 TooManyRequests " Error then "2." is the next level.

Also remember to take into account the response time required for "Payment Provider"