What Is Bolt.new? The In-Browser AI App Builder Explained
Bolt.new is an AI app builder from StackBlitz: you describe an app in chat, and it writes and runs a real full-stack project inside your browser. How it works, what it's good at, how hosting and pricing work, and what to check before real users arrive.
Bolt.new (usually just "Bolt") is an AI app builder made by StackBlitz. You describe what you want in a chat box — "a booking page for my yoga classes with a calendar and Stripe payments" — and Bolt writes the code, installs the packages and runs the app, right there in your browser.
Details as of October 2026; Bolt changes quickly.
How it works
Bolt's trick is StackBlitz's WebContainers technology, which runs a Node.js environment inside the browser tab. So when Bolt writes your app, it can actually install npm packages, start a dev server and show you a live preview without a remote machine for each project.
You work in a loop:
- Describe the app or the change.
- Bolt edits the code and the preview updates.
- Click around, find what's wrong, describe the fix.
You can open the code editor at any time to see — or change — the files Bolt wrote. Under the hood it's a normal JavaScript project, often React with Vite, which matters later if you want to move it. (What Is Vite?)
What it's good at
- Prototypes and MVPs you can click through within an hour.
- Landing pages, dashboards, internal tools.
- Seeing an idea before paying a developer, or before learning to code yourself.
Hosting, databases and agents
Bolt can publish your app to its own hosting or to Netlify, and has built-in options for a database and authentication. You can also export or sync the code to GitHub and host it anywhere. (How to Deploy a Bolt.new App)
Bolt offers several agents. In September 2026 it added Forge, a research-preview agent that runs on open-source models with much higher usage limits for people who opt in to sharing anonymised build sessions for training.
Pricing
Bolt has a free tier with limited usage and paid plans priced by how much AI work you do (tokens or usage). Big apps and long fix-it loops use more. Check bolt.new for current plans.
The limits to know about
- Fix loops. When the AI can't fix a bug, it can go round in circles burning usage. Step back, describe the problem differently, or roll back. (Stuck in an AI Fix Loop?)
- Security isn't automatic. Generated apps can ship with exposed keys or open database rules. (Vibe Coding Security Checklist)
- Backends grow. Long-running jobs, scheduled tasks and heavy databases eventually want a real server.
Bolt vs Lovable vs v0
All three turn chat into apps. Bolt runs everything in the browser with a full code view; Lovable is tightly integrated with its own cloud backend; v0 generates Next.js apps aimed at Vercel. (Lovable vs Bolt vs v0)
The summary
- Bolt.new writes and runs real web apps in your browser from a chat.
- Great for prototypes and MVPs; you can export the code anytime.
- Before real users: check security, back up data, and think about where the backend will live.
EasySpawn is where a Bolt app can grow up: a persistent server with Postgres, HTTPS and backups, and Claude Code on board to keep building it. See how it works for AI-built apps or join the waitlist.
Related: Choose an AI App Builder · What Is Lovable? · You Built an App With AI. Now What? · What Is Vibe Coding?
Keep reading
How to Deploy a Bolt.new App: Bolt Hosting, Netlify, or Your Own Server
Bolt.new can publish your app in one click, to its own hosting or to Netlify. What each option actually gives you, when to export the code and host it yourself, and the checks to run before you share the link with real users.
What Is v0? Vercel's AI App Builder Explained
v0 is Vercel's AI app builder: describe a UI or an app and it generates a real Next.js project with React, Tailwind and shadcn/ui, with a live preview and one-click publishing to Vercel. What it's good at, how it differs from Lovable and Bolt, and what to know before shipping.