Mini Apps · the long version

Ask for an app.
Get one.

Workflows automate the work. Mini apps give that work a face. Describe the little tool you want — "an app to log my daily food and chart it" — and Catalyst builds the workflows behind it, writes the app, and opens it live in your chat. It's a real, working tool you can use on the spot. No canvas, no front-end, no setup.

What a mini app is

A custom tool, generated on request.

A mini app is a small, single-purpose page built on top of your workflows and your data. You don't drag boxes around to make one — you ask the assistant for it, and it writes the whole thing. The Food Tracker below — photo button, today's totals, a chart it drew itself, an editable list of meals — was made by asking for one.

you ask, it builds

Describe it in plain language.

Tell the assistant what you want. It builds any workflows the app needs, writes the page, and hands you a working app — without you ever leaving the chat.

live, not a mockup

It runs the moment it appears.

The preview is the real app, running against your real data — not a picture of one. Use it on the spot. Don't like something? Say "make the tiles bigger, add a protein chart" and it changes.

a face over your work

Workflows are the verbs. Data is the storage.

An app sits on top of things you already have. It can run your workflows and read and write your data collections — that's how a button turns a photo into a logged, charted meal.

walled in by design

It can only touch what you grant it.

Every app runs in a locked-down sandbox with no way out to the open internet. It reaches Catalyst through one narrow, built-in bridge — and only the exact collections and workflows you let it use.

How one gets built

Describe it. Watch it appear.

01

Ask for the app.

Say what you want in chat — "a little app to log my food and show me a weekly chart." No template to pick, no blank canvas. The assistant takes it from there.

you "build me a food tracker"
02

It builds the pieces.

Catalyst wires up the workflows the app needs — a photo-to-calories workflow, a place to store each meal — then writes the app itself as a single, self-contained page.

built the analyze workflow photo → calories created collection food_log wrote the app tiles · chart · list
03

Use it right there.

The app opens as a live preview next to the chat — already running. Snap a photo, see today's total update, scroll the week. It's not a link you have to go click.

Live preview Real data Saved
04

Change it by talking.

"Add a protein chart." "Make it blue." The assistant edits the app and the preview updates. Every save is kept, so you can roll back to any earlier version.

Edit with AI Version history Restore
the result

A real tool,
not a chat reply.

What comes back isn't a wall of text — it's a working page. Buttons that run your workflows, tiles that read your data, a chart the app draws itself. Built for the one thing you asked for, and nothing else.

  • Runs your workflows. A button can kick off a workflow and show its result inline — like turning a photo into a logged meal.
  • Reads & writes your data. Today's totals, the weekly list, an inline edit or delete — all against your own collections.
  • Draws its own charts. Sparklines and bars are part of the app, not a screenshot — they update as your data does.
  • Lives in Apps. Every app you make shows up in one place to open, edit, or delete anytime.
catalyst · apps · food tracker
🍽 Food Tracker reads food_log
1,840 calories today
2,010 7-day average
this week
Chicken bowl 850 edit
Greek yogurt 180 edit
Apple 95 edit
runs · analyze_meal
reads · food_log
Safe by construction

Generated code, kept on a short leash.

A mini app is code an AI wrote — and one day, code someone else shared. So Catalyst treats every app as untrusted from the start. It runs walled off, with one tiny door, and that door only opens onto what you allowed.

sealed sandbox

No way out to the internet.

The app runs in a sealed-off frame with no network access of its own. It can't phone home, leak your data, or pull in anything from the outside.

never holds your login

It never sees your credentials.

Your sign-in stays with Catalyst, outside the app. The app can't read your session, your cookies, or anything else on the page around it.

grants

Only the collections and workflows you allow.

Each app spells out exactly which data collections and which workflows it's allowed to touch. Ask for anything outside that list and the request is refused.

one narrow bridge

Everything goes through one checkpoint.

The app talks to Catalyst through a single built-in bridge — run a workflow, read or write a collection. Every call is checked against its grants before anything happens.

rate-limited

A runaway app can't hammer your account.

Calls through the bridge are capped, so a buggy loop in a generated app can't run up a bill or pound the backend.

delete is clean

Deleting an app deletes only the app.

The workflows it ran and the collections it read are shared things you built — they stay put, and anything else using them keeps working.

Publish · Explore · Fork

An app you made, an app someone shares.

Once you've built something good, you can publish it. It lands in Explore — a public catalog anyone can browse with no account at all. And when you find an app you like there, you fork it: a clean copy in your own account, running on your models and your data. Nothing of the author's private side ever comes with it.

Browse the app store It's live now — no account needed to look.
publish

Flip it public, and it lists in Explore.

One switch shares your app. If it's backed by workflows, publishing makes the workflow logic readable by anyone — but your collections and the data inside them stay private. Only the recipe travels, never the pantry.

explore · no account

A public catalog anyone can browse.

Explore is open to the world — a featured row, a searchable grid, fork counts on every card. No sign-up to look around. A pure-code app even runs when you open it, with no account at all: try it before you ever join.

fork to run

Apps that use data ask you to fork first.

An app that runs workflows or reads data can't borrow the author's — so opening it offers "Fork this app to run it." You make it yours, then it runs on your models and your collections.

your own copy

A fork is genuinely yours.

Forking deep-copies the app's workflows into your account and lets you pick your own models. The author's data and secrets — saved keys, sign-ins, documents — never come along. You get the build, not their account.

catalyst · explore
🧭 Explore apps no account needed
Food Tracker forks · 214 fork
Habit Streaks forks · 96 fork
Tip Splitter forks · 41 use
publish · public
fork · your copy
finish setup

Pick your own models on the way in.

If a forked app leaned on models you don't have, a short finish setup step asks you to choose your own before it runs — so it works on your account from the first click.

lineage · update available

It remembers where it came from.

A fork keeps a quiet "forked from" link back to the original, and the original's fork count ticks up. When the author improves the source, you see an update available note — but your copy never changes on its own. It stays yours.

The editor

For when you want to get your hands in.

Most of the time, chat is enough. But every app also opens in a full editor — code on one side, the live app on the other, settings to the right — with an AI assistant built right in. Talk to it or type the code yourself; either way the preview keeps up.

code

The whole app, in one file.

An app is a single, compact component — small on purpose. Edit it directly, or let the assistant rewrite it for you.

live preview

See changes as you make them.

The running app sits next to the code, against your real data, and refreshes as you edit — so there's no guessing what a change will do.

edit with ai

Ask for changes in place.

The same assistant lives in the editor. "Add a monthly view." "Show macros too." It edits the app, and the preview updates.

properties & grants

Set the name, icon, and permissions.

A settings panel holds the app's name, emoji, and exactly which collections and workflows it's allowed to reach.

version history

Every save is recoverable.

Catalyst keeps a timeline of every save. Restore an earlier version and it lands as a new one — nothing is ever lost.

your own collections

Built on the same data layer.

Apps read and write the same named collections your workflows fill and your chats query — one place for your data, usable everywhere.

Ready to build a little tool?

Describe the app.
Skip the front-end.

The shortest path from "I wish I had a little app for this" to actually using one is the one where you just ask — and Catalyst builds the workflows, the data, and the app for you.

No credit card · Free forever for personal use · Docs →