Build a web app by describing it
B12 is an AI app builder. You describe the app you want in chat and B12 builds it, including the backend: user accounts, a database, payments, and bookings. It runs on your own domain with hosting and billing handled. Free to build, $24/month to launch.
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Join the 4M+ websites built with B12
Learn why real business owners choose B12 to power their online presence.
B12's AI has been a game-changer — intuitive, efficient, and truly supportive of our mission. It keeps The Rainbow Disruption running seamlessly.
Jarvis Sam
Exceptional service with a human touch. Highly recommended for anyone seeking a partner that values integrity and relationships just as much as technical excellence.
Poloko Ntshatsha
I was drawn to B12's use of AI, then seeing how nimble it was, I signed up that day. You literally click and it designs everything for you.
Gerry Sandusky
THANK YOU for creating such a user-friendly platform! Keep up the great work, your design makes a real impact for small business owners like me!
Brian Fenlon
B12's AI has been a game-changer — intuitive, efficient, and truly supportive of our mission. It keeps The Rainbow Disruption running seamlessly.
Jarvis Sam
Exceptional service with a human touch. Highly recommended for anyone seeking a partner that values integrity and relationships just as much as technical excellence.
Poloko Ntshatsha
I was drawn to B12's use of AI, then seeing how nimble it was, I signed up that day. You literally click and it designs everything for you.
Gerry Sandusky
THANK YOU for creating such a user-friendly platform! Keep up the great work, your design makes a real impact for small business owners like me!
Brian Fenlon
B12's AI has been a game-changer — intuitive, efficient, and truly supportive of our mission. It keeps The Rainbow Disruption running seamlessly.
Jarvis Sam
Exceptional service with a human touch. Highly recommended for anyone seeking a partner that values integrity and relationships just as much as technical excellence.
Poloko Ntshatsha
I was drawn to B12's use of AI, then seeing how nimble it was, I signed up that day. You literally click and it designs everything for you.
Gerry Sandusky
THANK YOU for creating such a user-friendly platform! Keep up the great work, your design makes a real impact for small business owners like me!
Brian Fenlon
Describe it the way you'd tell a person
There's no form to fill out and no schema to design first. You chat with B12 the way you'd brief a developer, and it builds the screens, logic, and backend to match. A few examples of what people actually type:
- “Add a login page with email signup and send a confirmation when someone registers.”
- “Turn this CSV into a pricing table customers can filter.”
- “Set up a booking page that takes payment and syncs with my calendar.”
What “backend” actually means
Most AI builders can generate a page. Fewer can generate the parts underneath it that make an app actually work:
- User accounts and access
- Sign up, log in, and permissions, so visitors become known users.
- Database and storage
- A place to hold customer records, orders, files, and anything else your app needs to remember.
- Payments and bookings
- Take payment and schedule appointments without a separate processor.
- Connections to other tools
- Stripe, Calendly, and anything else with an API, wired into the app you describe.
B12 builds all of this on Supabase, a production database, so what you get is a real backend, not a demo. See how B12's backend works in more detail on the backends page.
How B12 compares to Base44, Replit, Bolt.new, and Bubble
Every AI app builder in this category makes a different tradeoff between how much it builds for you and how much control it hands back. Here's where each one lands:
Scroll to see every column →
| B12 | Base44 | Replit | Bolt.new | Bubble | |
|---|---|---|---|---|---|
| Backend included | Yes, on the Website plan and up. Accounts, a database, storage, payments, and bookings, built on Supabase. | Yes. Database, authentication, and storage are built into every plan. | Partial. A built-in database and optional Replit Auth, but no built-in payments. | No. You connect your own Supabase project for a database and auth. | Yes. A native database and visual workflows power the app. |
| Hosting and domain | Included. Launch on your own domain with hosting handled. | Custom domain needs a paid plan, which includes a free domain for the first year. | Custom domain and public deployment need a paid plan. | Custom domain needs the Pro plan. | Free plan is development only. A live app and custom domain need the Starter plan. |
| Payments | Built in on the Website plan and up. Take payments and bookings without connecting a separate processor. | Native Stripe integration, available on the Builder plan and up. | No built-in payment product. You wire up Stripe yourself in code. | Native Stripe integration, once Supabase and a Stripe account are connected. | Native Stripe plugin covers checkout, subscriptions, and refunds. |
| Who it's for | Small businesses and service providers who want a finished app, not a codebase to maintain. | Non-technical builders shipping quick internal tools or consumer apps. | Developers who want to write, own, and export real code. | Developers and technical builders prototyping full-stack apps fast. | No-code builders who need custom logic and are willing to learn Bubble's editor. |
| Free tier | Yes. Publish a live site on a b12sites.com subdomain for free. | Yes. 25 message credits a month and up to 5 apps. | Yes, but it can't publish a live app with a custom domain. | Yes. 1 million tokens a month, no custom domain. | Yes, but you can't launch a live, public app on it. |
| Price | Starts at $24/month (Website plan). | Starts at $20/month. | Starts at $25/month (Core plan). | Starts at $25/month (Pro plan). | Starts at $32/month (Starter plan). |
Figures above reflect each vendor's own pricing and documentation pages as of August 2026. Paid prices shown are each vendor's lowest published standard monthly (month-to-month) starting price, not a discounted annual rate; features and limits vary by plan.
Where B12 is, and isn't, the right fit
B12 is built to get you from a description to a working app fast: a real domain, hosting, a backend, and billing, without you setting any of it up. That's a strong start you then make yours with edits in chat.
It's not the right tool if you want to own and export a full codebase and deploy it yourself on your own infrastructure. If that's the goal, Replit or Bolt.new fit better, since both hand you real, exportable code. B12 fits businesses and service providers who want a finished, running app and don't want to hire a developer or maintain a repo to get one. See how B12's plans compare on the pricing page, or read how it stacks up as a website builder on the AI website builder page.
Don't want to touch code at all? See our guide to the best no-code app builder.
Frequently asked questions
An AI app builder is a platform that turns a plain-language description into a working web app. You describe what you want in chat, and the AI writes the code, sets up the screens, and often the backend, instead of you hiring a developer or learning to code.
It depends on the tool. B12, Bubble, and Replit build the backend as part of the app: B12 and Bubble include a database, user accounts, and storage, and Replit includes a database by default plus an optional built-in Replit Auth for logins. Bolt.new can generate backend code, but you typically connect and manage a separate database yourself, such as Supabase. Base44 builds a backend in too, similar to B12 and Bubble.
An AI website builder mainly generates pages: copy, images, and layout for a site visitors read. An AI app builder adds the parts a site does not need on its own: logins, a database, payments, and workflows that respond to what a user does. B12 covers both from one product, so a site can grow into an app without switching platforms.
Most AI app builders offer a free tier for building and testing, then charge once you want to launch publicly on your own domain. Starting paid prices in this category run from about $20 to $49 a month at standard, month-to-month rates, though what is included at that price varies a lot: some plans cover hosting and a domain, others charge extra for those, or for the database and payments.
Yes, on most of these platforms. B12 and Bubble build payment and checkout in. Base44 and Bolt.new connect to Stripe once you set up an account and, for Bolt.new, a connected Supabase project. Replit does not offer a built-in payment product, so you would wire up Stripe yourself in code.
Describe your app and see it built
Start for free and get a working app with a backend, a domain, and billing handled. Launch when you're ready.
