How to Use methods Parameter in Route in Flask

In Flask, use the methods parameter in the @app.route() decorator to specify which HTTP methods a route accepts, like GET or POST. For example, @app.route('/', methods=['GET', 'POST']) allows the route to handle both GET and POST requests.

Syntax

The methods parameter is a list of HTTP methods that a Flask route will accept. It is passed as an argument to the @app.route() decorator.

• @app.route(path, methods=[...]): Defines the URL path and allowed HTTP methods.
• methods: A list of strings like 'GET', 'POST', 'PUT', 'DELETE', etc.

python

@app.route('/path', methods=['GET', 'POST'])
def function_name():
    pass

Example

This example shows a Flask app with a route that accepts both GET and POST requests. It returns different messages depending on the request method.

python

from flask import Flask, request

app = Flask(__name__)

@app.route('/', methods=['GET', 'POST'])
def home():
    if request.method == 'POST':
        return 'This is a POST request'
    else:
        return 'This is a GET request'

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

Output

When accessed via browser (GET): This is a GET request
When accessed via POST (e.g., curl or form): This is a POST request

Common Pitfalls

Common mistakes when using the methods parameter include:

• Not specifying methods defaults the route to only accept GET requests.
• Using a string instead of a list for methods causes errors (e.g., methods='POST' instead of methods=['POST']).
• Forgetting to handle different methods inside the view function can cause unexpected behavior.

python

from flask import Flask, request

app = Flask(__name__)

# Wrong: methods as string
@app.route('/wrong', methods='POST')
def wrong():
    return 'This will cause an error'

# Right: methods as list
@app.route('/right', methods=['POST'])
def right():
    return 'This works fine'

Quick Reference

Parameter	Description	Example
methods	List of HTTP methods the route accepts	methods=['GET', 'POST']
GET	Retrieve data, default method if methods not set	methods=['GET']
POST	Send data to server	methods=['POST']
PUT	Update data	methods=['PUT']
DELETE	Delete data	methods=['DELETE']

Key Takeaways

Use the methods parameter as a list to specify allowed HTTP methods in @app.route().

If methods is not set, the route only accepts GET requests by default.

Always handle different request methods inside your view function using request.method.

Pass methods=['POST'] not methods='POST' to avoid errors.

Common HTTP methods include GET, POST, PUT, and DELETE.