Copyleaks V1 API has been deprectaed and will reach it's end of life on July 1st 2020.
See newer version documentation - Copyleaks V3 API.
You can add custom payload to the request headers. The payload is stored in a 'dictionary' representing a collection of string key and string value pairs.
To create a new payload with the key
Message and the value 'Hello world!', add the following header to your request:
copyleaks-client-custom-Message: Hello world!
The custom fields limitations are: