Evaluations, or evals, are the secret ingredient for exceptional AI products. Crafting great prompts and choosing powerful models is important, but evals are what shape the reliability, usability, and ultimately, the success of AI systems. An eval is made up of clearly defined tasks (the scenarios your AI model needs to perform), scorers (success criteria), and datasets (the curated inputs that test your task’s capability).
If you think of experiments in Braintrust like making a pull request to your repository, eval playgrounds are like editing and refining code in your IDE. We built eval playgrounds to complement experiments and provide an environment that significantly accelerates the iteration loop by letting you run full evaluations directly in a powerful editor UI.
Playgrounds embed tasks, scorers, and datasets directly into a single intuitive UI. You can:
Playgrounds maintain state and allow you to run the same underlying Eval capabilities as formal experiments. You can quickly iterate, refine, and optimize parameters before committing to a formal snapshot. This approach means you can experiment more freely, collaborate more effectively, and achieve higher productivity across your AI teams.
Customers using eval playgrounds in production consider it to be a critical part of their eval workflow. To support their expanding needs, the Clinical AI team at Ambience Healthcare transitioned from earlier methods involving manual data handling and separate prompt repositories to a more cohesive and advanced toolkit with Braintrust. With playgrounds, they've:
Playgrounds fundamentally changed how we iterate—we move twice as quickly without sacrificing precision.
Evaluating an AI system has multiple parts: assessing nuanced decision-making, responsiveness to changing conditions, and safe outcomes, even in unpredictable environments. Eval playgrounds let you do all of this in one place by combining quick iteration, side-by-side trace comparisons, and scalable large dataset runs. This design enables AI teams to:

Eval playgrounds provide the design-driven approach and rapid iteration necessary to turn good ideas into great business outcomes. Try playgrounds today to rapidly iterate towards better AI products.