Yes, it's pretty reliable. We (mailgun.com) use it in production, our deployment handles thousands of requests/sec, we have not seen any flask-related issues s

Yes, it's pretty reliable. We (mailgun.com) use it in production, our deployment handles thousands of requests/sec, we have not seen any flask-related issues so far in 2+ years. You can use pool of flask + twisted powered services behind nginxes: Nginx ---upstream pool--> twisted.wsgi + thread pool + flask app Something like that: https://gist.github.com/klizhentas/5775158 https://gist.github.com/klizhentas/5775158