Send File on Post as base64 Data

Dear all,
I’m looking for a way to post the File/Image content to an api.
I am using the
Right now i just receive the URI like “content://” from android and “blob:https://editor . apphive . io/e17bf9c6-24d6-4b92-b484-0ff574xxxxxx” but i need to get the content in base64 or similar posted into my api.

Do i need to use the firebase database?
Is there anoter way?