January 2026
I am happy to announce a new way of building behavioral experiments: OTAI, the oTree AI builder.
OTAI is an AI chat agent that follows your instructions and writes oTree apps for you. This means you can build fully working experiments (including complex multiplayer games) without writing any code.
These days, AI helpers seem to be popping up in every website and app we use. Some may not seem that useful. So, I understand that some people feel skeptical when they see another AI tool. But please give OTAI a try. A lot of thought and design has gone into developing it.
I predict that soon, 90% of oTree users will be using OTAI. It's that much faster and more efficient.
You can use OTAI directly in your web browser. It automatically downloads every update to a folder on your hard drive, so that you can test updates by playing them live in oTree's development server (devserver).
OTAI was built as a response to problems we've seen with these tools.
These tools are good at quickly producing results that initially look very impressive. But later on, the problems become apparent. You notice the app has many bugs, and fixing one bug introduces other bugs. At this point, unless you are a professional software developer, it is hard to get this code fully functioning. We have seen first-hand how much of a researcher's time can be wasted in this process.
OTAI's LLM is specially trained to write oTree code and meet high standards of correctness demanded by research. For example, the OTAI system does not let the LLM directly write code. Instead, the LLM provides instructions and then the OTAI system writes the actual code. This protects your apps from hallucinations and other problems.
As a result, the code you get with OTAI will be much more consistent than anything you can get with a general-purpose LLM.
Link: Try OTAI