Describe an app. Use it seconds later.
Type what you want and it's running in about three seconds. Keep talking to change it.
Real model, real time, no cuts.
Seconds, not minutes
Every app in the video was built live, each in under five seconds.
Talk to change it
Ask for a dark mode, a new feature or a different layout. Every reply is a version you can go back to.
Yours to share
Publish it with a link, or download one HTML file that runs anywhere.
Why it's this fast
Special chips
Most AI runs on graphics cards that keep fetching the model from separate memory, like a chef walking to the pantry for every ingredient. 1two3 runs on Cerebras chips, which keep the model in fast memory built into the chip itself, so everything is within arm's reach.
A right-sized model
The AI is Qwen 3.8, an open model from Alibaba with 27 billion parameters (the numbers that hold what a model has learned). That's mid-sized by today's standards: big enough to write a good app, small enough to answer in a blink.
No build step
Each app is one small file of plain code, with no frameworks or servers to set up. Your browser checks it and starts it in a few thousandths of a second.
- 1two3 · Qwen 3.8 on Cerebras2.5 s
- Claude Sonnet 5.5, a popular AI model26 s
- Qwen 3.8 on Alibaba's own servers82 s
1two3's time was measured. The others are calculated from output speeds measured by Artificial Analysis (141.2 and 43.7 tokens per second, October 2026). Those speeds leave out the wait for the first word; our 2.5 seconds includes it.
Questions
Speed
Is the video sped up?
No. It was recorded in real time on the same setup you'll use, and the timer on screen is the actual build time.
Does faster mean lower quality?
The speed comes from the chips, not from cutting corners. The model still thinks before it writes, and that thinking is part of the two seconds. For one-screen apps, a mid-sized model does the job well. For large software with many parts, bigger and slower models still have the edge, and that isn't what 1two3 is for.
What you can build
What can I build?
Single-screen apps that run in your browser: tools, calculators, trackers, timers, quizzes, games and visualisations.
Can my app save data, sign people in or show live information?
Not yet. Apps run in a locked-down sandbox: they can't save data between visits, reach the internet or use outside code libraries. That keeps them safe to open and share, but it means no databases, logins or live data like weather or prices for now.
Can I make a website or an online shop?
A simple one-page site, yes. Multiple pages, payments and custom domains aren't supported yet.
Does it work on phones?
Yes, and you can preview any app at phone size. Most apps adapt to small screens on their own. If one doesn't, ask it to fix the mobile layout.
Pricing
How does pricing work?
Pay as you go, with no subscription. Load credit ($10, $25 or $50) and each build or change uses a little of it, depending on how much the AI had to think and write. Most builds cost a few cents, and you see the cost of each one in the chat. Sharing, downloads and syncing across your devices are included.
What happens when my credit runs out?
Building pauses until you add more. Your balance is always in the top corner, and you'll get a heads-up when it's running low. Apps you've already made and shared keep working.
Does credit expire?
No. Unused credit stays on your account.
Your apps
Can I take my app elsewhere?
Yes. Download any app as one HTML file. It runs in any browser, and you can host it anywhere.
How do I share an app?
Click Share to publish it at a link anyone can open. You can update or unpublish it anytime.
Are my projects private?
Yes, until you publish them. When you're signed in they sync to your account, so they're on all your devices. Your prompts are sent to our AI provider to generate the app.