zaher ideally you should use Celery as giorgosp mention but if it is mandatory to return result for API request then you can use Gunicorn
gunicorn --workers 3 -b localhost:8000 main:app --reload
Here, in above code I have mention 3 workers so at a time you can serve/process 3 requests.
Ideally no of workers can be
cpu_count * 2 + 1
You can use any port number you like, but make sure that it is above 1024 and it's not used by any other program.
The main:app option tells Gunicorn to invoke the application object app available in the file main.py.
Gunicorn provides an optional --reload switch that tells Gunicorn to detect any code changes on the fly. This way you can change your code without having to restart Gunicorn.
And if this approach is not suitable for your need than I think you should use Tornado instead of Falcon.
Let me know if any further clarification needed.