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What is py4web?



PY4WEB is a web framework for rapid development of efficient database driven web applications. It is an evolution of the popular web2py framework but much faster and slicker.


Running py4web


The main Dashboard


Editing a file in the Dashboard


Editing a database in the Dashboard



PY4WEB runs fine on Windows, MacOS and Linux. There are many installation procedures (see the official documentation for details) but only two of them are summarized here.

The simplest way to install py4web is using binaries, but it's only available for Windows and MacOS. It's meant especially for newbies or students, because it does not require Python pre-installed on your system nor administrative rights. You just need to download the latest Windows or MacOS ZIP file from this external repository. Unzip it on a local folder and open a command line there. Finally run the commands (omit './' if you're using Windows)

./py4web set_password
./py4web run apps

The standard installation procedure for py4web on Windows, MacOS and Linux is using pip. Its only prerequisite is Python 3.7+.

python3 -m pip install --upgrade py4web --no-cache-dir --user

but do not type the ''--user'' option with virtualenv or a standard Windows installation which is already per-user. Also, if ''python3'' does not work, try with the simple ''python'' command instead.

This will install the latest stable release of py4web and all its dependencies on the system's path only. After the installation you'll be able to start py4web on any given working folder with

py4web setup apps
py4web set_password
py4web run apps

Launch Arguments

# py4web run -h


   Run all the applications on apps_folder

-Y, --yes                     No prompt, assume yes to questions  [default:
-H, --host TEXT               Host name  [default:]
-P, --port INTEGER            Port number  [default: 8000]
-p, --password_file TEXT      File for the encrypted password  [default:
-s, --server [default|wsgiref|tornado|gunicorn|gevent|waitress|
                              server to use  [default: default]
-w, --number_workers INTEGER  Number of workers  [default: 0]
-d, --dashboard_mode TEXT     Dashboard mode: demo, readonly, full,
                              none  [default: full]
--watch [off|sync|lazy]       Watch python changes and reload apps
                              automatically, modes: off, sync, lazy
                              [default: lazy]
--ssl_cert PATH               SSL certificate file for HTTPS
--ssl_key PATH                SSL key file for HTTPS
--errorlog TEXT               Where to send error logs
                              [default: :stderr]
-L, --logging_level INTEGER   The log level (0 - 50) [default: 30
-D, --debug                   Debug switch [default: False]
-help, -h, --help             Show this message and exit.


py4web run -H -P 8000 -d demo apps

Note that since the default (as specified above) for the host and port are and 8000 respectively, the above command can be shortened to:

py4web run -d demo apps

Tell me more

  • it is 10-20x faster than web2py
  • python3.7+ only
  • uses (same DAL as web2py) for database connection
  • uses the same validators as web2py (they are in pyDAL)
  • uses yatl (same as web2py but defaults to [[...]] instead of {{...}} delimiters) and Renoir for html templates
  • uses the very similar html helpers to web2py (A, DIV, SPAN, etc.)
  • uses for i18n and pluralization
  • request, response, abort are from, using ombott (One More BOTTle), which is a fast bottlepy spin-off
  • HTTP and redirect are our own objects
  • like web2py, it supports static asset management /{appname}/static/_0.0.0/{path}
  • implements sessions in cookies (jwt encrypted), db, memcache, redis and custom
  • implements a cache.memoize (Ram cache with O(1) access) Memoize
  • supports multiple apps under apps folder (same as web2py)
  • unlike web2py does not use a custom importer or eval (this allow simple debugging with standard IDE)
  • admin has been replaced by a _dashboard
  • appadmin has been replaced by dbadmin (within _dashboard)
  • auth logic is implemented via a "auth" vue.js custom component
  • it comes with a Form object (like SQLFORM on web2py)
  • it comes with a Grid object providing grid and CRUD capabilities
  • it supports htmx
  • this is a work in progress and not stable yet but close to being stable
  • there are not enough tests


Special thanks to Sam de Alfaro, that designed the official logo of py4web. We friendly call the logo "Axel the axolotl": it magically represents the sense of kindness and inclusion we believe it's the cornerstone of our growing community.


Many thanks to everyone who has contributed to the project, and especially: