Will I get performance boost combining concurrent.futures with Flask

This is dependent on more factors than Flask, like what you are using in front of Flask (gunicorn, gevent, uwsgi, nginx, etc). If you find that your request to "some_url" is indeed a bottleneck, pushing it to another thread might provide a boost, but again that depends on your individual circumstances; many elements in a web stack can make the process "slow".

Instead of multithreading on the Flask process (which can quickly get complicated), pushing blocking I/O to a helper process might be a better solution. You can send Redis messages to a process running on an asyncio event loop, which will scale well.

app.py

from flask import Flaskimport redisr = redis.StrictRedis(host='127.0.0.1', port=6379)app = Flask(__name__)@app.route("/")def hello():    # send your message to the other process with redis    r.publish('some-channel', 'some data')    return "OK"if __name__ == '__main__':    app.run(port=4000, debug=True)

helper.py

import asyncioimport asyncio_redisimport aiohttp@asyncio.coroutinedef get_page():    # get some url    req = yield from aiohttp.get('http://example.com')    data = yield from req.read()    # insert into mongo using Motor or some other async DBAPI    #yield from insert_into_database(data) @asyncio.coroutinedef run():    # Create connection    connection = yield from asyncio_redis.Connection.create(host='127.0.0.1', port=6379)    # Create subscriber.    subscriber = yield from connection.start_subscribe()    # Subscribe to channel.    yield from subscriber.subscribe([ 'some-channel' ])    # Inside a while loop, wait for incoming events.    while True:        reply = yield from subscriber.next_published()        print('Received: ', repr(reply.value), 'on channel', reply.channel)        yield from get_page()    # When finished, close the connection.    connection.close()if __name__ == '__main__':    loop = asyncio.get_event_loop()    loop.run_until_complete(run())