Parsing published data

I have been trying unsuccessfully to parse data I’m publishing to particle and then onto adafruit.io using a Webhook. Specifically I’m trying to send a value, lat and lon to adafruit but the moustache variables are not parsing the published elements.

My publish value looks like this:

{ 'value': '0', 'lat': '43.627125', 'lon': '-79.360458'}

When I create a Webhook I am sending via JSON the following:

{
  "value": "{{value}}",
  "lat": "{{lat}}",
  "lon": "{{lon}}"
}

These {{}} variables are nil - they don’t parse out of the published data

Note: If I substitute real values instead of the {{}} ones it does work!

Any ideas on what I am doing wrong?
philly