Hello,
I have previously completed this work as an AWS Lambda function powered by NodeJS. With a few monitor modifications it would be usable for your requirements.
Alternatively I would be happy to accommodate developing this in an alternative language of your choosing (hence the slightly longer estimate on time).
Please do not hesitate to contact me on freelancer's chat if there is anything I can do to help further.
Sincerely,
Stephen Lombard
Your API Expert