#python route @app.route('/this-route', methods=['GET', 'POST']): def thisRoute(): information = request.data return "1" #javascript const URL = '/get-coordinates' const xhr = new XMLHttpRequest(); sender = JSON.stringify([[1, 2, 3], [4, 5, 6], [7, 8, 9]]) xhr.open('POST', URL); xhr.send(sender);