Ask HN: Can I use third party payment processor in Google play for my app?

Hi, My app generates custom map based on photos in user's device. Although, the app is free to access, the custom map generation takes place in the server, and is a paid service. Users can also upload their photos to the website through the web browser and generate the same map (after payment). The output files are in pdf or kml formats, so they can be opened with or without my app. In this case, am I bound to use Google in-app payment? Or, can I use third party payment processor as well?

Would I get to discuss with a Google app consultant before they would red flag or ban my app for third party payment processor integration?