oTree

Note

February 2026 update: OTAI allows you to build oTree apps through a chat interface, without coding. It’s highly trained on oTree experiments.

Live demos

https://www.otreehub.com/projects/?featured=1

Homepage

http://www.otree.org/

About

oTree is a framework based on Python that lets you build:

Multiplayer strategy games, like the prisoner’s dilemma, public goods game, and auctions
Controlled behavioral experiments in economics, psychology, and related fields
Surveys and quizzes

Support

For help, post to our forum.

Contents:

Installing oTree
- Important note
- Choose your editor
- oTree installation
About Python
- Tutorial file
Tutorial
- Part 1: Simple survey
- Part 2: Public goods game
- Part 3: Trust game
Conceptual overview
- Sessions
- Subsessions
- Groups
- Object hierarchy
- Participant
OTAI
Models
- Fields
- Built-in fields and methods
Pages
- is_displayed()
- vars_for_template()
- before_next_page()
- timeout_seconds
- Wait pages
- Randomizing page sequence
- app_after_this_page
- Back button
Templates
- Template syntax
- How templates work: an example
- Images (static files)
- Includable templates
- JavaScript and CSS
- Bootstrap
- Charts
- Number formatting
Forms
- Forms in templates
- Simple form field validation
- Dynamic form field validation
- Determining form fields dynamically
- Widgets
- {{ formfield }}
- Customizing a field’s appearance
- Raw HTML widgets
- Preserving unsubmitted inputs
- Buttons
- Miscellaneous & advanced
Multiplayer games
- Groups
- Wait pages
- Chat
Apps & rounds
- Apps
- Rounds
Treatments
- Treatment groups & multiple rounds
- Balanced treatment groups
- Choosing which treatment to play
- Configure sessions
Timeouts
- Basics
- Advanced techniques
Bots
- Running bots
- Writing tests
- Advanced features
Live pages
- Sending data to the server
- Sending data to the page
- Example: auction
- Data
- History
- ExtraModel
- Keeping users on the page
- Asynchronous live methods (AI, web APIs, etc)
- General advice about live pages
- Troubleshooting
Server setup
- Basic Server Setup (Heroku)
- Ubuntu Linux Server
- Windows Server (advanced)
Admin
- Password protection
- Start links
- Participant labels
- Arrival order
- Customizing the admin interface
- Export Data
- Debug Info
- Payments
Rooms
- Creating rooms
- Configuring a room
- Using rooms
- Room welcome pages (consent forms, etc)
Currency and Decimal
- Currency
- DecimalField
MTurk & Prolific
- MTurk
- Prolific
Miscellaneous
- REST
- Localization
- Tips and tricks
- Advanced features
- Bots: advanced features
- oTree Lite
- Version history
- The new no-self format

Indices and tables

Index
Module Index
Search Page

(Thank you to contributors)