Bolt

What Is Bolt?

Bolt is an AI app builder from StackBlitz. You describe a web application and it builds one — but unlike most tools in this category, it does not hide what it is doing. You get a real file tree, a real terminal and a live preview, all running inside the browser tab you are already looking at.

That is possible because StackBlitz spent years building the technology to run a Node.js toolchain client-side. Package installs, the dev server, the build — none of it goes to a remote sandbox. The practical effect is that the preview updates about as fast as it would on your own machine, and nothing queues behind other people's builds.

The result sits somewhere between an app builder and an editor. If Lovable is for people who want to describe an app and not think about code, Bolt is for people who want to describe an app and then look at it.

How It Works

Describe, Then Intervene

You prompt, it writes files, the preview refreshes. When something is wrong you can either explain it in another message or open the file and fix it yourself — and the second option is often faster, cheaper and more accurate. Being able to drop into the code without leaving the tool is the core of what makes Bolt different from its competitors.

It is also stack-agnostic in a way the vendor-backed builders are not. React, Vue, Svelte, Astro, whatever JavaScript framework you prefer — it is a real Node environment, not a template engine with one blessed output.

A Complete Application, Not Just a Front End

Databases are included and unlimited even on the free plan, with a choice of provider on Pro. Hosting comes with the account, custom domains on paid plans, and deployment is a button rather than a pipeline. For a prototype that needs to store something and be visited by someone, this covers everything.

Import and Export

Because it is a genuine development environment, existing projects can come in and finished ones can go out. That matters more than a feature list suggests: the tools that trap your work are the ones you regret, and this is not one of them.

Tokens: Read This Before You Subscribe

Bolt bills by token, and there is one fact about how tokens are consumed that determines whether you will be happy with it.

StackBlitz says it plainly in its own FAQ: most token usage comes from syncing your project's file system to the model, so the larger the project, the more tokens each message costs. A one-line instruction on a mature application is not a small request. This is not a flaw unique to Bolt — every tool in this category has the same problem — but Bolt is unusually honest about it, and the company states that reducing token usage is a priority.

The consequences are practical. Costs rise as your project grows, which is the opposite of how people instinctively budget. Starting a fresh project is cheap; finishing a big one is not. And the free tier's daily cap means the first serious day of work will end early.

One genuinely good piece of news: on Pro, unused tokens roll over to the next month. Among the AI builders — several of which expire credits aggressively — that is a rare piece of customer-friendly design.

What It Costs

Yearly billing saves up to 28 per cent. Pro starts at ten million tokens a month and scales upward if you need more, so twenty-five dollars is the entry price rather than the price.

The free tier is more useful than most: a million tokens a month with hosting and databases included is enough to build and publish something small. The three-hundred-thousand daily ceiling is the constraint that will actually bite — it caps how much you can do in one sitting rather than how much you can do in total.

Who Gets the Most From It

Developers Who Want to See the Code

The natural audience. Generate the scaffolding, then behave like a developer: read the files, fix the two things the model got wrong by hand, prompt for the next feature. That loop is faster than pure prompting and far cheaper in tokens.

Anyone Building Outside React

Because it runs a real Node environment rather than generating into one preferred stack, Bolt is the obvious choice if your project is in Vue, Svelte, Astro or anything else that the framework-specific builders treat as a second-class citizen.

People Teaching or Learning to Build

Seeing the files appear, the terminal run and the preview update makes the connection between description and implementation visible. As a way of learning what an application actually consists of, it beats a tool that only shows you the finished screen.

Fast Prototyping With Real Data

Databases and hosting included, deployment in a click, no local setup at all. From opening the tab to a live URL that stores something is a short trip.

What to Watch Out For

• Token cost grows with project size, so the app gets more expensive to work on exactly as it gets more valuable.
• The free plan's 300K daily ceiling ends a productive session early, regardless of your monthly allowance.
• Pro's $25 covers ten million tokens; heavier use costs more, so treat the headline as a starting point.
• Everything runs in the browser, which is fast but means a heavy project can make the tab itself sluggish.
• Editing files by hand is possible and often necessary — this is not a tool for someone who refuses to look at code.
• Generated code needs the same review as any AI output, particularly around authentication and anything storing user data.
• Free-tier sites carry Bolt branding, so client work needs a paid plan.
• Long conversations accumulate context. Starting a fresh chat for a new feature is often cheaper than continuing an old one.

Frequently Asked Questions

Is Bolt free?

Yes, with a usable free plan: one million tokens a month, capped at three hundred thousand a day, plus hosting, unlimited databases and both public and private projects. Sites built on it carry Bolt branding.

What are tokens and why do mine disappear so fast?

Tokens measure the text sent to and from the model. StackBlitz states that most consumption comes from syncing your project's files to the AI, which means a bigger project spends more per message. Short prompts on a large codebase are not cheap.

Do unused tokens roll over?

On Pro, yes — they carry into the next month. That is unusual among AI builders and worth weighing against competitors that expire credits.

How is it different from Lovable or v0?

Bolt shows you the file tree and the terminal and lets you edit directly; it is also framework-agnostic. Lovable is smoother if you never want to see code, and v0 is stronger if you are committed to React and Vercel. Bolt sits closest to being an actual development environment.

Can I use my own framework?

Within the JavaScript ecosystem, yes — it is a real Node environment running in the browser, so most frameworks and npm packages work as they would locally.

Can I deploy and use a custom domain?

Hosting is included on every plan, with a click to publish. Custom domains and the removal of Bolt branding come with Pro.

The Bottom Line

Bolt is the AI builder that respects the possibility you might know something. It gives you the environment as well as the output, works with whatever JavaScript stack you prefer, and rolls unused tokens forward instead of confiscating them. For anyone who intends to read the generated code, it is the most comfortable of the current crop.

Budget for the fact that token cost rises with project size, and get in the habit of fixing small things by hand rather than by prompt. Done that way, the free tier will tell you within an evening whether the rest is worth paying for.