Jane Street Designer Reports Shift From Figma to Claude for Core Prototyping

A Jane Street designer now builds functional prototypes with Claude Code more often than Figma mockups or spec documents. Primary source data shows the workflow change occurred after joining the firm in summer 2024, with Figma use dropping sharply in the prior two months as model capability and prompt scope improved. The same post records specific outputs including a 2000-line JSQL LLM-prompting feature, interactive app prototypes, and visual-design iterations performed entirely inside the editor. Related industry measurements from the 2024 Stack Overflow Developer Survey and the Anthropic Economic Index both register rising LLM adoption for UI and feature work among professional teams, confirming the displacement pattern first quantified in the Jane Street account. These sources together document measurable reduction in ancillary artifacts such as component libraries and review decks once working code replaces them. The original post notes one remaining process gap: reviewers receive finished implementations rather than early sketches, limiting upstream input on functionality.