Cannot call http post (json) request

ESPHome
1

I’m trying to call a http_request.post within a script that should address a JSON key into the fabulous WLED API. Now with endless attempts I’m stuck, not knowing what to do next.

If I understand the WLED api well (described here), a post request in JSON shall look like, for example:

{"seg":[{"on":[[0,true]]}]}

This example should turn on the first segment (#0) in a LED strip.

When embedding this in the http_request it looks like:

# Setup HTTP request component
http_request:
#  useragent: esphome/device
#  timeout: 10s
    
script:
  id: ondownup
  then:
    - http_request.post:
        url: http://192.168.1.61/json
        headers:
          Content-Type: application/json
        json:
          key: {"seg":[{"on":[[0,true]]}]}
        verify_ssl: false

I am obviously not a crack in this, but hope that someone can give me insight why this won’t go. ESPhome gives the message that this shall be a string (as in within quotes), however, that seems not to work.