How to Connect to Flask Local Server

Can't connect to Flask web service, connection refused

Run your app like this:

if __name__ == '__main__':
    app.run(host='0.0.0.0')

It will make the server externally visible. If the IP address of the machine is 192.168.X.X then, from the same network you can access it in 5000 port. Like, http://192.168.X.X:5000

Configure Flask dev server to be visible across the network

While this is possible, you should not use the Flask dev server in production. The Flask dev server is not designed to be particularly secure, stable, or efficient. See the docs on deploying for correct solutions.

The --host option to flask run, or the host parameter to app.run(), controls what address the development server listens to. By default it runs on localhost, change it to flask run --host=0.0.0.0 (or app.run(host="0.0.0.0")) to run on all your machine's IP addresses.

0.0.0.0 is a special value that you can't use in the browser directly, you'll need to navigate to the actual IP address of the machine on the network. You may also need to adjust your firewall to allow external access to the port.

The Flask quickstart docs explain this in the "Externally Visible Server" section:

If you run the server you will notice that the server is only
accessible from your own computer, not from any other in the network.
This is the default because in debugging mode a user of the
application can execute arbitrary Python code on your computer.
If you have the debugger disabled or trust the users on your network,
you can make the server publicly available simply by adding
--host=0.0.0.0 to the command line:
$ flask run --host=0.0.0.0
This tells your operating system to listen on all public IPs.

How to access Flask test server from the outside of local network?

What you'll need to do is make your specified port available on your router. This is done with port forwarding. The location of this tab can switch depending on your router provider but once this is done you can just visit This link which shows your public IP. Then you can just visit: 000.00.000.00:5000 <-- Replace zero's with public IP.

Connect to Flask Server from other devices on same network

I solved the issue by changing my home network profile to private instead of public, which allows my PC to be discoverable. Completely overlooked that!

Hope this helps someone!

Unable to connect to Flask local server

http://0.0.0.0 often doesn't work, you will likely need to switch to http://localhost:8080 in your browser.

Also validate you have set flask to use 0.0.0.0 and not 127.0.0.1.

I figured I should explain the second part, within a routes.py file you want to make sure you set the host to 0.0.0.0 otherwise you won't be able to access it. So at the bottom of your routes.py make sure you have:

from flask import Flask
app = Flask(__name__)
app.run(host="0.0.0.0")

How to access Flask web server from mobile device?

You need to run the app with your IPv4 address

app.run(debug=True, host= '192.168.8.103') assuming 192.168.8.103 is your IPv4 if not, replace it with your IPv4

How to Host a Flask website from localhost 5000

I am assuming what you're asking is to host your flask web site so others can view it. The address you mention in your post is the local host address for your computer and is only accessible from your own computer. If you only want someone on your same network (WiFi) to access it, you would need to replace "127.0.0.1" with the IP address of your computer. You would also likely have to open up a firewall on your computer to allow the port 5000.

However, if you want anyone on the internet to access your site, there are a ton of ways to do this but since you mentioned AWS, you can do this easily by running a small EC2 instance (virtual server). If you have a new AWS account and have not already run any EC2 in that account, you can actually run a small EC2 instance for free for a whole year. Great for small projects. If you're just getting started with EC2, you may want to go here https://aws.amazon.com/ec2/getting-started/

Basic steps:

Spin up an EC2 instance. Choose the default Amazon Linxu 2 OS type, make sure to create/assign a key pair so you can later ssh into it, make sure the Allow SSH from anywhere setting is checked/selected and the Allow HTTP checkbox is checked (not HTTPS).
Wait for the instance to launch.
Log into your instance by clicking on your ec2 instance in the list of ec2 instnaces and click the Connect button, click the Connect button again (Instance connect tab). If that doesn't work, follow the steps on the SSH client tab.
Install flask

pip3 install flask

Clone your git repo

git clone https://github.com/some0ne14/Math-Ibex.git

Change to your repos' folder

cd Math-Ibex/Math-Practice-Website-master

Edit your main.py so that the app.run line looks like the following (you can do this on GitHub before you run git clone actually or use the nano command to edit the file easily). This allows the system to run on the standard web port 80.

app.run(host='0.0.0.0', port=80, debug=True)

Run the following to start the application. If you want to run it as a service so you can walk away or close the terminal and it will still stay running, just search on here how to run flask as a service.

python3 main.py

You can now connect to your server with any web browser using your EC2 instance's public IP address or generated AWS DNS name (available on the EC2 instnace property page).
Make sure to stop your instance when not using it to save those free runtime minutes.

Connecting to localhost using Python-flask on Google Colab?

Try to run your app like this:

if __name__ == '__main__':
    app.run(host='0.0.0.0',port=5000)

This also makes the server externally visible. If the IP address of the machine is 192.168.X.X then, from the same network you can access it in 5000 port.

It could also be an issue with the firewall, in which case, do the following:

sudo ufw allow 5000

Edit:

Since you are running on Google Colab and not on your local system. The running steps would vary.

Do note that

Google Colab provides a VM(virtual machine) so we cannot access the localhost(all it does it route it to our local machine’s localhost) as we do on our local machine when running a local web server. What we can do is expose it to a public URL using ngrok. Here comes the Python library flask-ngrok.

Follow the steps here to get it running with flask-ngrok

Flask access from different devices

refer first to this doc (section Externally Visible Server) on how to expose your local Flask app to make it accessible from trusted devices in your network for testing purposes.

$(venv) flask run --host=0.0.0.0

or in your app.py

from flask import Flask
[..]
app = Flask(__name__)
[..]
if __name__ == "__main__":
   app.run(host="0.0.0.0", port=5000, debug=True)

and then :

$(venv) python app.py

but if it happens and you got this error dial tcp 0.0.0.0:5000: connect: connection refused then try to use the local ip address (192.168.x.y instead of 0.0.0.0) of the machine hosting your Flask app. you may find this thread usefull