What is vibe coding? Definition, limits, and the tools that do it

The short answer

Vibe coding means building software by describing what you want, in plain language, to an AI that writes the code for you. You move forward by talking (“add a button,” “fix this error”) instead of reading or writing the code. By extension, the term covers the tools that turn a description into an app: Lovable, Bolt, Base44 or Replit, among those automascope tracks.

The term comes from a post published on February 2, 2025 by Andrej Karpathy, an AI researcher, describing a way of programming where you forget the code is even there (Andrej Karpathy, post on X). He was talking about low-stakes weekend projects. The meaning has widened since.

One example: a quote tracker for a painting company

A house-painting company wants a small internal tool: a form to enter a quote, a list you can filter by status, and email sign-in for two people. Here is how the project goes, according to what the vendors describe.

1. You describe the app in a few sentences, the way you would brief a contractor.
2. The tool generates a first version: the pages, the database, the user sign-in.
3. You ask for changes, one message at a time: an extra column, an export, a color.
4. You publish to an address the tool provides, or to your own domain depending on the plan.

Every message you send to the AI uses units. That is the point to understand before you choose.

What vibe coding does not solve

• The code exists even if you never read it. A security hole, an open access path or a math error is still your responsibility. Once the app holds customer data, have the code read by someone who can read it.
• Fixes cost units too. On Base44’s free plan, automatic AI fixes use credits.
• The cost per message rises with project size. On Bolt, most of the usage comes from reading the project’s files: the bigger the project, the more each message costs.
• The running app uses units as well. On Lovable, one balance pays for building, the backend and the AI features of published apps; when the balance runs out, the backend is paused. On Base44, the built-in services of the running app draw on a second meter, integration credits. On Replit, publishing is paid from credits.
• Your content may be used to train models. Bolt’s terms grant the vendor model-development licenses unless the user opts out. Base44 states that, outside the Enterprise plan, data may be used for training, with no opt-out setting.
• Leaving the tool is not always simple. Code export depends on the plan, and the backend can hold you: on Lovable, the only way off the built-in backend is to Supabase.

Table scrolls horizontally →

Four vibe coding apps, row by row

Criterion	LovableApp builder	BoltApp builder	Base44App builder	ReplitApp builder
Billing unit	creditssource	tokenssource	message creditssource	dollars of creditssource
Free plan	30 credits per monthsource	1,000,000 tokens per monthsource	25 message credits per monthsource	Yessource
App type	Web apps; no React Native project and no built-in submission to the iOS or Android stores.source	Websites, web apps, and prototypes; iPhone and Android mobile apps with Expo.source	Web apps and websites; files for the App Store and Google Play (web view) from Builder up.source	Web and mobile apps (Expo); submission to Apple through its beta service, Google Play not yet supported.source
Database	"Cloud" backend (database, authentication, storage) built on Supabase's open-source foundation.source	Built-in database per project, with authentication, storage, and server functions; Supabase on Pro and Teams.source	Built-in database and authentication, included in all plans.source	Managed PostgreSQL and built-in object storage; authentication through Replit Auth or Clerk.source
Code export	Two-way GitHub sync on all plans; .zip download on paid plans.source	Project download as a zip file; GitHub sync on the main branch only.source	Two-way GitHub sync and zip export from the Builder plan up.source	Built-in Git, GitHub sync from the Git pane, branches managed in the editor, import of a GitHub repository.source
Custom domain	Paid plans only; automatic SSL certificate; domains can be purchased within Lovable.source	Paid plans only; purchase within Bolt or connection of a domain.source	From the Starter plan up; free domain for 1 year on annual plans.source	Custom domain added in the publishing settings; default address on .replit.app.source
Vendor	Visit Lovable (opens in a new tab)	Visit Bolt (opens in a new tab)	Visit Base44 (opens in a new tab)	Visit Replit (opens in a new tab)

What this changes when you pick a tool: the billing unit

The four tools do not count the same thing. Take the painter’s tool and assume 40 messages to reach a usable version.

• Lovable counts credits, and the cost per message varies with complexity: 0.50 credit to change a button color, 1.20 to add authentication, according to the vendor’s examples. At those rates, 40 messages come to between 20 and 48 credits; heavier requests cost more. The Free plan gives 5 credits a day, capped at 30 credits a month. The Pro plan starts at 100 credits.
• Base44 counts message credits: about 0.5 for a simple visual change, 3 to 4 for a broad change, according to its estimates. The 40 messages come to between 20 and 160 credits. The Free plan gives 25 a month, 5 a day at most; Starter gives 100 and Builder 250.
• Bolt counts tokens, with no per-message rate: usage depends on the size of the project. The Free plan gives 1,000,000 tokens a month with a limit of 300,000 a day. The Pro plan starts at 10,000,000 tokens. Edits you make by hand in the code use none.
• Replit counts credits expressed in dollars and bills its agent by effort: the longer it works on a request, the more that request costs. The vendor publishes no price per request, so the project cannot be priced in advance.

The same project comes out as a range of credits on two tools and as no possible figure on the other two. The guide to billing units goes back over that difficulty. The Lovable pricing, Bolt pricing, Base44 pricing and Replit pricing pages give the full grids.

Which tool for which situation

• If you want a mockup to show or a simple internal tool, start by comparing the free plans and their daily caps in the AI app builders comparison.
• If keeping the code matters to you, look at the “Code export” row of the table: GitHub sync and download are not open on every plan.
• If you are aiming for a mobile app, the answers differ. Lovable produces web apps. Bolt and Replit build mobile apps with Expo; on Replit, publishing to Google Play is not supported yet. Base44 generates, from the Builder plan up, files for the app stores where the app runs in a web view.
• If you are torn between two tools, the Lovable vs Bolt, Lovable vs Base44, Lovable vs Replit and Base44 vs Replit pages compare them row by row.
• If what you need is to connect apps that already exist, that is automation, not vibe coding: see the guide to no-code automation.

The Lovable, Bolt, Base44 and Replit pages detail hosting, the database and code ownership, with sources.