The first iteration of the Zalando Assistant launched in 4 German and English-speaking markets in 2023. Based on its success, the Zalando team set the goal of expanding the Assistant into 20+ markets in 2024.

This required refining and scaling the Assistant’s personalization capabilities. To serve markets across Europe, the team needed an AI solution that could perform well in over 20 languages.

They also needed the Assistant to follow nuanced instructions. GPT‑3.5, which powered the first iteration of the Assistant, wasn’t best equipped for instruction-following tasks. For instance, when users asked for seasonal outfits or event-specific attire, the results were often too generic.

Working closely, the Zalando and OpenAI teams identified two investment areas: Improving the evaluation process—referred to as an evaluation framework or “evals”—and upgrading the model powering the Assistant.