Thanks Shoya, this is a bit more clear that Messaging API premium could available only in Japan. I did not get a clear answers from Line support Thailand on this question. I did try to ask them 3 times but I always got same answers with "You have to subscribe Line@" which did not answer my question.
Unfourtunately my Japanese language skill is zero so I have to put this project on-hold until Line Thailand turn on Messaging API as premium program.
Thank you very much.
Japanese Messaging API premium pricing is on following page. https://at.line.me/jp/plan
I checked english page ( https://at.line.me/en/plan ) but, there was no. I guess premium pricing avalilable only for Japan.
If you want to know about more Japanese info, I'll answer. thanks.
Taiwan also has paid version of Messaging api and I belive Thaialnd is launching soon.
I still wait they opening in Thailand soon.
As a Re-design, your developer trial plan(limited;50 friends) should be migrated as a new free plan before this summer.
Free plans are now limited to only 500 push messages. This is not a reasonable limit when you have 511 friends! One broadcast message and it's completely consumed.
We need 5000! Not 500. This is the same issue with Friends being 50 originally.