Sending JSON to Flask, request.args vs request.form

You are POST-ing JSON, neither request.args nor request.form will work.

request.form works only if you POST data with the right content types; form data is either POSTed with the application/x-www-form-urlencoded or multipart/form-data encodings.

When you use application/json, you are no longer POSTing form data. Use request.get_json() to access JSON POST data instead:

@app.route('/testpoint', methods = ['POST'])
def testpoint():
    name = request.get_json().get('name', '')
    return jsonify(name = name)

As you state, request.args only ever contains values included in the request query string, the optional part of a URL after the ? question mark. Since it’s part of the URL, it is independent from the POST request body.