class RegexConverter(BaseConverter):
    def __init__(self, map, *args):
        BaseConverter.__init__(self, map)
        self.map = map
        self.regex = args[0]


app.url_map.converters['regex'] = RegexConverter

Define a regex route

@app.route('/go/<regex("[a-zA-Z0-9]+"):url>')
def go(url):
    real_url = redis.get(url)
    return redirect(real_url)