How to run dialog in slack app with flask?

You had 2 issues in your code:

• you need to use an access token, not a verification token in the callto dialog.open
• you need to send the dialog definition as JSON, not as as form array

I made these additional changes- Added code for using a slack token defined as environment variable- Use the get() method to access form parameters in from the request- Added code to show the API response from dialog.open

Here is a corrected version of your code:

import osimport requestsfrom flask import Flask, json, requestapp = Flask(__name__) #create the Flask app@app.route('/helpdesk', methods=['POST'])def helpdesk():    api_url = 'https://slack.com/api/dialog.open'    trigger_id = request.form.get('trigger_id')    dialog = {        "callback_id": "ryde-46e2b0",        "title": "Request a Ride",        "submit_label": "Request",        "notify_on_cancel": True,        "state": "Limo",        "elements": [            {                "type": "text",                "label": "Pickup Location",                "name": "loc_origin"            },            {                "type": "text",                "label": "Dropoff Location",                "name": "loc_destination"            }        ]    }    api_data = {        "token": os.environ['SLACK_TOKEN'],        "trigger_id": trigger_id,        "dialog": json.dumps(dialog)    }    res = requests.post(api_url, data=api_data)    print(res.content)    return make_response()if __name__ == '__main__':    app.run(debug=True, port=8000) #run app in debug mode on port 8000