Playground

Try Jev without joining the waitlist

TypeSafe is issuing API keys in batches, so most people who read about Jev cannot actually try it yet. This page runs real calls against the live model — pick a question type, edit the criteria, see what comes back.

State — what you're asking about

114 / 4000

Question type

Instructions

Options — name, and when to pick it

What to look at

The interesting part is not the winning option — it is the distribution underneath it. Edit an option's description and watch the probabilities move: those descriptions are the entire prompt surface of a Choice question, and writing them well is most of the skill in using Jev.

Try making the state genuinely ambiguous. A confident answer on an easy input tells you nothing; a 0.4 confidence on a borderline one tells you exactly where your threshold needs to sit.