A comprehensive guide to implementing light, dark, and system theme switching in TanStack Start applications without flickering issues. Covers the challenges of server-side rendering with themes, including FOUC prevention through inline scripts, safe localStorage handling, CSS-driven UI controls, and proper hydration management. Includes practical code examples for theme providers, storage utilities, and validation with Zod.
Table of contents
Implementation DetailsTanStack Start primitives: clientOnly and createIsomorphicFnValidate with ZodCookies vs LocalStorage (and when to use them)Wrap‑upLeonardo Montini FollowSort: