v0 and Bolt are both AI tools that turn prompts into working code. v0 is known for generating fast, polished React/Next.js UI (built by Vercel, tuned for shadcn/ui output). Bolt is known for a full in-browser dev environment (WebContainers) with broader framework support beyond React. Neither is objectively "better." The right pick depends on what you're optimizing for.
Choose v0 if you are building a Next.js/React interface and want the cleanest UI output fastest. Choose Bolt if you want a full-stack scaffold you can run and edit entirely in the browser, regardless of framework.