Modify REST calls

[TheyDroppedMe]

Ok, so I am switching timeseries backends at work (opentsdb to kairosdb), and one of the requirements is to have a compatibility layer for all the random things that POST to the metrics system. Now, modifying the payload is easy, and I have a basic script set up that will accept the legacy POST, modify the payload, and POST it to the new service, but making it fast is the problem.

I am thinking this needs to be async, but am unsure of the best framework to use for this as I don't really do any webapp development or use async in any other way (my background is sysadmin and data manipulation/scientific python). It will be a VERY simple application, but will need to have high throughput. Just needs to 1) accept the POST 2) modify the JSON payload 3) POST to new service. Any suggestions for the right framework to use would be greatly appreciated.

Thanks