Best for getting a working prototype in front of someone the same day
Bolt.new was the tool that made prompt-to-app mainstream. Its advantage over rivals is that a real Node runtime executes in your browser tab, so what you are looking at is the actual application rather than a preview of one.
Best for larger projects where other prompt-to-app tools lose coherence
Emergent sits between the prompt-to-app builders and the autonomous agents: you converse rather than prompt once, and a set of agents carries the work through to deployment. Its large context window shows on projects where rivals lose the thread.
Best for prototypes and non-engineers shipping a working app
Replit is the only tool here that owns the whole path from prompt to live URL: editor, database, hosting and deploys in the browser. That makes it excellent for prototypes and a poor fit for established engineering teams.