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Describe an app. Prello plans it, asks what matters, and builds it.

Describe an app. Say what you want in a sentence.
It asks what matters. Up to three questions that change the app, while it builds.
Prello plans it. It turns your answers into a short plan.
It builds it. From a ready-made base, it adds what the app needs.
It checks every file. It checks every file it writes and repairs broken ones.

Open Studio Mac & iPhone early access Scroll to watch it build

stillwater-yogaNew projectBuildingBuilding · 1 questionBuildingReady

Stillwater Yoga

This week's classes

MonTueWedThuFri

07:00Morning flow45 min · 6 spots leftBook

12:15Lunch stretch30 min · 2 spots leftBook

18:30Yin and breath60 min · FullJoin waitlist

20:00Candle flow50 min · 1 spot leftBook

Checking 29 filesclass-list.tsx · line 42 · unclosed tagRepaired · 29 of 29 files pass

PromptA booking app for my yoga studio, with accounts and a waitlist when a class is full.

Plan · 4 steps

Class schedule
Sign in and accounts
Booking a spot
Waitlist for full classes

Question

Who will use this app?

My teamPublic / customers

Who uses it: customers

Ready-made base

Database

Design tokens

29 of 29 files pass

Prello is live

One line. A working app.

Describe it once, watch it build, then keep shaping it. Music only, no voice.

The build is an example, drawn from what the product does today.

One run, step by step

Watch it build.

stillwater-yogaBuilderNew projectBuildingBuilding · 1 questionBuildingReady

A booking app for my yoga studio: class schedule, accounts to sign in, and a waitlist when a class is full.

Started from a ready-made project

Sign inDatabaseDesign tokens

Who will use this app?

Just meMy teamPublic / customers

The primary user shapes the flows and defaults.

Who uses it: customers

Plan · 4 steps

1Class schedule
2Sign in and accounts
3Booking a spot
4Waitlist for full classes

Writing files

Wrote 8 files

Checking 29 files

class-list.tsx had an error

42: JSX element 'ClassList' has no corresponding closing tag.

All 29 files pass · 1 repaired

−<ClassList classes={week}

+<ClassList classes={week} />

Ready. Keep going here, or open it in Code.

A booking app for my yoga studio: class schedule, accounts to sign in, and a waitlist when a class is full.Ask for a change

FilesPreview

Ready-made

package.jsonready-made

app/layout.tsxready-made

lib/db.tsready-made

lib/auth.tsready-made

Written for you

app/page.tsx+64

app/schedule/page.tsx+88

components/class-list.tsx+71

components/book-button.tsx+39

lib/bookings.ts+52

app/api/book/route.ts+44

lib/waitlist.ts+47

components/waitlist-button.tsx+31

Stillwater YogaSign in

This week's classes

MonTueWedThuFri

07:00Morning flow45 min · 6 spots leftBook

12:15Lunch stretch30 min · 2 spots leftBook

18:30Yin and breath60 min · FullJoin waitlist

20:00Candle flow50 min · 1 spot leftBook

An example project, shown step by step and sped up. The steps are the ones the Builder takes on a real build.

How it works

It keeps building while you decide.

A build starts as soon as you press Build. Beside it, Prello asks up to three questions that change the app, like who will use it. Early answers go into the build that is running, and later ones are built right after it.

Before your first feature

Every app starts ahead.

Every build begins from a ready-made project, not a blank page, so your usage goes to the parts that make your app yours.

A ready-made base Sign in, a database and design tokens, added when the app needs them.

The parts people forget Written from templates, not by a model.

A check of what is missing The project page reads your files and lists it.

Plan once, write at once

One model plans. The writing runs at once.

By default, a stronger model reads your brief, plans up to ten files and decides how to write them: files that must agree are written together, and independent parts at the same time, by a model picked for cost and quality.

Plan · stronger model

1app/page.tsx
2app/schedule/page.tsx
3components/class-list.tsx
4components/book-button.tsx
5lib/bookings.ts
6lib/waitlist.ts

One writer per file, side by side · leaner model

app/page.tsxwriting+64

app/schedule/page.tsxwriting+88

components/class-list.tsxwriting+71

components/book-button.tsxwriting+39

lib/bookings.tswriting+52

lib/waitlist.tswriting+47

All 6 written. Next, every file is checked.

It checks its own work.

Every file it writes is checked, and broken ones go back with the exact error to be repaired. If one is still wrong, the build says so.

Every change is a step you can undo.

In Code, each AI edit is a checkpoint with its diff. Read what changed and put any file back the way it was.

Design

Every design gets a grade.

Fixed rules grade each page from A to F, so the same page always gets the same grade. Tap a suggestion and Design redraws the page as the next version.

3 components · Minimal · AIv1v2Example

Stillwater Yoga

Find your class

Morning flowLunch stretchYin and breath

Stillwater Yoga

Find your class

Morning flowLunch stretchYin and breath

C · 7.4/10B · 8.2/105.1:1 · AA

Add padding (at least 1rem) to sections and cardsAdd @media queries for mobile breakpointsAdd subtle shadows, borders, or gradients for visual depth

RefineAdd @media queries for mobile breakpoints

3questions at most, asked while it builds
6basics in every app, from templates
2repair rounds for a file that breaks
8checks behind every design grade
0added on top of your own key

Builder · Design · Code

One project. Three ways in.

Start from an idea.

Describe the app. Prello plans it, asks what matters, builds it on a ready-made base and checks every file it writes.

All three work on one project, so you can move between them at any time.

At the limit, you choose what happens.

Settings shows your managed usage as three bars, for six hours, the week and the month. At the limit, Prello carries on with your OpenRouter key if you saved one. Turn that off and it stops instead, with your chat message saved.

Pricing

Models at cost. Nothing added to your key.

Bring your own key from OpenRouter, Anthropic, OpenAI, Groq, Fireworks, DeepInfra or Together, and Prello adds nothing on top. Premium and up also includes managed usage at cost, and you see what is left as one bar.

Annual plans cost ten months.

BYOK Limited$0/moLocal only: it runs on your own device with your own key. Steer it from your other devices as they arrive.Early access

BYOK$7/moYour own key, no managed usage. Unlimited runs and cloud projects.Choose

Premium$20/moManaged usage at cost, the base for every plan above. No Prello mark on your apps.Choose

Power User$60/mo3.2× Premium’s usage. Loops run side by side.Choose

Professional$120/mo2× Power User’s usage. Loops run side by side.Choose

Ultra$240/mo2× Professional’s usage. Loops run side by side.Choose

EnterpriseCustomCustom usage, set with you.Talk to Prello

Pick a plan to pay for it now, or start in the Studio and choose later.Open Studio

VISAAMEX Pay Pay

Secured by Polar, our merchant of record. Cards and wallets, monthly or annual, cancel any time.

Plain answers.

Do I need to know how to code?

No. You describe the app and answer a few questions. If you do code, the Code view is a real editor on the same files.

Which AI models does it use?

By default a stronger model plans each build, and the files are written by a model picked for cost and quality, so the strong model works where it counts. You can also pick a model yourself.

What does at cost mean?

Managed usage, included in Premium and up, is billed at what the models cost, with no markup. With your own key, your provider bills you and Prello adds nothing.

How are my keys kept safe?

They are encrypted with AES-256 on Prello's servers and used only to call the provider they belong to.

What if the AI writes a broken file?

Prello checks every file it writes and sends broken ones back to be repaired, up to two times. If something is still wrong, the build says so instead of hiding it.

Can I change the app after it is built?

Yes. Ask for a change in the Builder, adjust the look in Design, or edit the files in Code. Every AI edit in Code is a checkpoint you can undo.

Why early access for the apps?

The Studio is open in your browser now. The Mac and iPhone apps go out in batches, so every group gets an app that works, and what early users say shapes what comes next.

Can I compare a few directions in Design?

Yes. Turn on 3 variants and Design writes a Minimal, a Structured and an Expressive version at the same time, each with its own score and contrast check. Pick one and it becomes your next version.

What if Design can't reach a model?

It draws the page from its own templates instead and labels that version template, not AI, so you know which kind you got.

Can Prello lower my usage limits?

Not by surprise. A smaller usage window is announced in the app and by email at least 30 days before it starts, and a smaller month never starts inside a period you have already paid for.

Where can I use Prello?

In your browser now, on desktop and phone. The Mac and iPhone apps are in early access. One account and one seat work everywhere.

Where is Prello made?

In Sweden.

Prello for Mac

The same Studio, as an app that also does the work.

Builder, Design and Code, the same as in your browser.
Runs sessions on your own Mac as well as in Prello Cloud.
The free plan runs on your Mac with your own AI key.

Prello for iPhone

Keep your builds moving when you are away from the desk.

Follow running sessions live, on the Lock Screen too.
Answer questions, steer a build or start a new one by voice.
See each build as it comes along and open the live app in Safari.

macOS · iOS

The Mac and iPhone apps are next.

The Studio is open in your browser now, on desktop and phone. The Mac and iPhone apps are in early access: leave your email and your invite comes when a seat opens. The free plan runs on your own Mac with your own AI key.

PrelloEarly access
boarding pass
Pending

Access ID

—

Holderawaiting email

AppsmacOS · iOS

Boardswhen a seat opens

Describe an app. Prello plans it, asks what matters, and builds it.

Describe an app. Say what you want in a sentence.

It asks what matters. Up to three questions that change the app, while it builds.

Prello plans it. It turns your answers into a short plan.

It builds it. From a ready-made base, it adds what the app needs.

It checks every file. It checks every file it writes and repairs broken ones.

It checks its own work.

Every file it writes is checked, and broken ones go back with the exact error to be repaired. If one is still wrong, the build says so.

Every change is a step you can undo.

In Code, each AI edit is a checkpoint with its diff. Read what changed and put any file back the way it was.

Describe an app. Prello plans it, asks what matters, and builds it.Describe an app.

One line. A working app.

Watch it build.

It keeps building while you decide.

Every app starts ahead.

One model plans. The writing runs at once.

It checks its own work.

Every change is a step you can undo.

Every design gets a grade.

One project. Three ways in.

Start from an idea.

Start from a look.

Start from the code.

At the limit, you choose what happens.

Models at cost. Nothing added to your key.

Plain answers.

Prello for Mac

Prello for iPhone

The Mac and iPhone apps are next.

Describe an app. Prello plans it, asks what matters, and builds it.Describe an app.

One line. A working app.

Watch it build.

It keeps building while you decide.

Every app starts ahead.

One model plans. The writing runs at once.

It checks its own work.

Every change is a step you can undo.

Every design gets a grade.

One project. Three ways in.

Start from an idea.

Start from a look.

Start from the code.

At the limit, you choose what happens.

Models at cost. Nothing added to your key.

Plain answers.

Prello for Mac

Prello for iPhone

The Mac and iPhone apps are next.

Describe an app. Prello plans it, asks what matters, and builds it.

Describe an app. Prello plans it, asks what matters, and builds it.