I'm working on Somleng (https://github.com/somleng) - an Open Source alternative to Twilio, that's being used to save lives by powering the National Early Warning Systems of Cambodia and Laos.

We're also building OpenEWS (https://github.com/somleng/open-ews) which will be the world's first Open Source Early Warning System Dissemination Platform.

We're a small 2 person team trying to make a big difference.

Somleng (https://www.somleng.org/case_studies.html) is my Open Source project which is helping to save lives and improve the lives of children around the world. It's being used to power Early Warning Systems as well as improve maternal health.

You don’t actually need to use the AMI. Here’s an example of a NAT instance we build from scratch:

https://github.com/somleng/somleng-project/blob/main/infrast...

Paypal use a callback method for their IPNs

I meant the mentioned method by which the client polls back to the API for request/transaction status.