How to build a Python API with Flask

Flask is a popular micro-framework for building web applications in Python. It is lightweight, flexible, and easy to use, making it a great choice for developing APIs. In this article, we will walk you through the steps to build a simple API with Flask.

Step 1: Install Flask

Before we can start building our API, we need to install Flask. You can do this by running the following command:


pip install Flask


Step 2: Create a Flask App

Next, we need to create a new Python file for our Flask application. Let’s call it app.py. In this file, import the Flask module and create a new instance of the Flask class:


from flask import Flask
app = Flask(__name__)


Step 3: Define Routes

Routes in Flask map URL patterns to Python functions. Let’s define a simple route that returns a JSON response:


@app.route('/')
def hello_world():
return {'message': 'Hello, World!'}


Step 4: Run the Flask App

Finally, we can run our Flask application using the following command:


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


Now you can access your API by visiting http://localhost:5000 in your browser. You should see the message ‘Hello, World!’ displayed on the screen.

Conclusion

Congratulations! You have successfully built a simple API with Flask. This is just the beginning – Flask offers a lot of features and flexibility for building more complex APIs. Happy coding!