Piwik API: specify segment in JSON

Question

Good day!

I have Piwik/Matomo tracking traffic on MyWebsite. I'd like to use the API to export data on browser languages, but only for a specific section of MyWebsite (the one that contains MySection in the url). Is it possible to specify this segment in the JSON request? How does it work? Something like:

'{
    "date_from": "'.$dateStart.'",
    "date_to": "'.$dateEnd.'",
    "website_id": "'.$siteId.'",
    "offset": 0,
    "segment": {"pageUrl": "@"'.$mySectionUrl.
'}}'

In this article on API Segmentation with GET request it seems to be possible adding a "@" for contains but it's not shown how to achieve the same effect with JSON.