v0 is an AI app builder made by Vercel: a chat-based service in which a person describes an application in plain language and an AI agent writes the code. It builds landing pages, dashboards, components and full-stack applications (with both the user interface and the server and database side).
The user types a prompt, or attaches a screenshot or a Figma design, and v0 plans the work, writes the code and shows a live preview. Design mode changes details with visual controls instead of new prompts. v0 can connect the app to databases and outside APIs, push the code to a GitHub repository or open a pull request, and deploy the result to Vercel's hosting in one step. An iOS app lets people build from a phone.
It is a hosted service. A free plan has a daily message limit; paid plans are monthly subscriptions per user that include credits, and extra use is billed by the tokens (pieces of text) that the models read and write.