How to deploy a Flask app in Vercel, so that I can use it as an API endpoint

Question

Error: The provided path “~/Desktop/deploy/app.py” is a file, but expected a directory. Please choose a different one. ? In which directory is your code located? ./ 🔗 Linked to my-projects/deploy (created .vercel) 🔍 Inspect: https://vercel.com/aayushpaigwars-projects/deploy/69UJ1cLzH8gkgXAapSANhkD [2s] ✅ Production: https://deploy-3mtixmu03-aayushpaigwar.vercel.app [2s] Error: Unable to find any supported Python versions.

I tried vercel deployment by creating a vercel.json file inside that I entered:

{
    "builds": [
        {
            "src": "./app.py",
            "use": "@vercel/python"
        }
    ],
    "routes": [
        {
            "src": "/(.*)",
            "dest": "/app.py"
        }
    ]
}

Answer 1

There is a really nice Vercel template for Flask.

Here is how you can do that easily:

You need to have a "vercel.json" file in the root of the project, with the following content:

# vercel.json

{
  "rewrites": [
    { "source": "/(.*)", "destination": "/api/index" }
  ]
}

Then, create a "requirements.txt" file in the root of the project:

# requirements.txt

Flask==3.0.0

Then, create a "api" folder with the index.py file:

# api/index.py

from flask import Flask

app = Flask(__name__)

@app.route('/')
def home():
    return 'Hello, World!'

@app.route('/about')
def about():
    return 'About'

That's it! now deploy it and everything should work as expected. Just send a GET request to '/' or '/about' and you will see the content.

Source: https://vercel.com/templates/python/flask-hello-world