Saint-Louis Fed: market and economic data

import requests

xml_url = 'https://api.stlouisfed.org/fred/series/search?search_text=monetary+service+index&api_key=28f276e1de4f557efeda57da7a217cc2&file_type=xml'
json_url = 'https://api.stlouisfed.org/fred/series/search?search_text=monetary+service+index&api_key=28f276e1de4f557efeda57da7a217cc2&file_type=json'

json_url_sp500 = 'https://api.stlouisfed.org/fred/series/observations?series_id=SP500&api_key=28f276e1de4f557efeda57da7a217cc2&file_type=json'
req = requests.get(json_url_sp500)
req

<Response [200]>

req.content[:1000]

b'{"realtime_start":"2024-04-08","realtime_end":"2024-04-08","observation_start":"1600-01-01","observation_end":"9999-12-31","units":"lin","output_type":1,"file_type":"json","order_by":"observation_date","sort_order":"asc","count":2610,"offset":0,"limit":100000,"observations":[{"realtime_start":"2024-04-08","realtime_end":"2024-04-08","date":"2014-04-07","value":"1845.04"},{"realtime_start":"2024-04-08","realtime_end":"2024-04-08","date":"2014-04-08","value":"1851.96"},{"realtime_start":"2024-04-08","realtime_end":"2024-04-08","date":"2014-04-09","value":"1872.18"},{"realtime_start":"2024-04-08","realtime_end":"2024-04-08","date":"2014-04-10","value":"1833.08"},{"realtime_start":"2024-04-08","realtime_end":"2024-04-08","date":"2014-04-11","value":"1815.69"},{"realtime_start":"2024-04-08","realtime_end":"2024-04-08","date":"2014-04-14","value":"1830.61"},{"realtime_start":"2024-04-08","realtime_end":"2024-04-08","date":"2014-04-15","value":"1842.98"},{"realtime_start":"2024-04-08","realti'