Release v8.4.0. (Changelog)

webargs is a Python library for parsing and validating HTTP request objects, with built-in support for popular web frameworks, including Flask, Django, Bottle, Tornado, Pyramid, Falcon, and aiohttp.

Upgrading from an older version?#

See the Upgrading to Newer Releases page for notes on getting your code up-to-date with the latest version.

Usage and Simple Examples#

from flask import Flask
from webargs import fields
from webargs.flaskparser import use_args

app = Flask(__name__)

@use_args({"name": fields.Str(required=True)}, location="query")
def index(args):
    return "Hello " + args["name"]

if __name__ == "__main__":

# curl http://localhost:5000/\?name\='World'
# Hello World

By default Webargs will automatically parse JSON request bodies. But it also has support for:

Query Parameters

$ curl http://localhost:5000/\?name\='Freddie'
Hello Freddie

# pass location="query" to use_args

Form Data

$ curl -d 'name=Brian' http://localhost:5000/
Hello Brian

# pass location="form" to use_args


$ curl -X POST -H "Content-Type: application/json" -d '{"name":"Roger"}' http://localhost:5000/
Hello Roger

# pass location="json" (or omit location) to use_args

and, optionally:

  • Headers

  • Cookies

  • Files

  • Paths

Why Use It#

  • Simple, declarative syntax. Define your arguments as a mapping rather than imperatively pulling values off of request objects.

  • Code reusability. If you have multiple views that have the same request parameters, you only need to define your parameters once. You can also reuse validation and pre-processing routines.

  • Self-documentation. Webargs makes it easy to understand the expected arguments and their types for your view functions.

  • Automatic documentation. The metadata that webargs provides can serve as an aid for automatically generating API documentation.

  • Cross-framework compatibility. Webargs provides a consistent request-parsing interface that will work across many Python web frameworks.

  • marshmallow integration. Webargs uses marshmallow under the hood. When you need more flexibility than dictionaries, you can use marshmallow Schemas to define your request arguments.

Get It Now#

pip install -U webargs

Ready to get started? Go on to the Quickstart tutorial or check out some examples.

User Guide#

API Reference#

Project Info#