I'm using Google Maps API to show a map and carto.js (v4) to get the layer from carto and render on it. I want to know if it's possible to make the layer editable.
Apparently Google Maps API provides drawing tools so you can approach the task in a similar way as described in this old (but still valid) blog post.
At the end is all about converting those frontend geometries into INSERT statements and use CARTO SQL API, or more likely put some middelware in between to manage authentication and so on.