@uecken Replace the text box containing the URL with an unescaped text box. That way, the URL won't get truncated. See also this post: HTTP GET query parameters
I've got it. Replace the existing URL text box with an unescaped text box and type/paste the URL. There should be no more truncating at the question mark.
@csongor-varga: Yup, I'm experiencing the same issue with openweathermap.org. My HTTP GET URL gets stripped of all the parameters following the question mark. Modifying the Python code works, but there's no switching back to Blockly anymore.