Every organized person has a spreadsheet that became a monster. It started as a client list, grew columns, then tabs, then colors — and now nobody knows which version is the right one. The next step would be "hire someone to build a system," and that's where the idea dies: systems are expensive, slow, and become one more thing to maintain.
César solves this in a new way: you describe what you need, in a conversation, and walk out with a working app. Not a generic form, not a template — an app of your own, with your fields, your screens and your rules.
How it works: you talk, the app appears
In the builder, you write something like:
"I run a suit rental shop. I need to track clients, the suits with a photo and daily rate, and each rental with pickup date, return date and status."
César builds the app on the spot, with a live preview: you watch the screens take shape as you talk. Want a change? Just say it — "add a size field to the suit," "status should go from reserved to picked up to returned." When it's right, one click publishes. The app shows up in your menu, next to Finances, Trips and the other panels.
What you can build
The vocabulary is broad enough to cover what a person or a small business actually needs:
- Records your way — text, numbers, money, dates, phone numbers, photos, files, star ratings, locations. Required fields, unique values (two clients with the same phone? the app refuses) and validations with your own error messages.
- Relationships between things — each rental belongs to a client and can include several suits. The app understands and navigates those links on its own.
- Calculated fields — "rental days" from the dates, "client lifetime spend" summing their orders. Spreadsheet-style formulas, no programming.
- Step-by-step workflows — an order goes from draft to confirmed to delivered, and the app blocks illegal jumps.
- Screens that make sense — lists with search and filters, forms, drag-and-drop kanban, calendar, and a dashboard with numbers and charts (bar, line, pie): "this month's revenue," "active bookings."
- Automations and reminders — "the day before a return is due, ping me." Alerts go out through César's own notification pipeline: in the chat, on WhatsApp or on Telegram, respecting your quiet hours.
- Real working tools — per-record change history, trash bin, duplicate, bulk actions, auto-numbering.
The magic part: your app talks back
Here's what no traditional app builder does. Once published, your app becomes something you can just talk to César about — including on WhatsApp:
"Log a rental for Marina: two suits, pickup Friday, return Monday, $340"
"How much did I make on rentals this month?"
"Which returns are due tomorrow?"
You don't have to open a single screen. The app exists in the screens and in the conversation — and both doors touch the same data.
Buttons that actually do things
An app that only stores data is a pretty spreadsheet. What changes the game is that your app's buttons use the rest of César. You ask in one sentence:
"Add a Send quote button that generates the PDF and sends it to the client on WhatsApp"
And the button is born doing the whole chain: it reads the record, generates the PDF, sends it on WhatsApp, marks the order as sent. Before running, it shows the plan — step by step, who gets what — and asks for a single confirmation. Afterwards it shows what happened at each step, with the file ready to open.
The same goes for posting an expense to your finances, creating a calendar event, emailing a report, or asking César to write a text from the fields. There are screen-level buttons too: "mark all selected as paid", "export what I'm seeing to PDF" — that last one every list already has, no asking needed.
Every capability the app uses is consented when you publish and can be revoked any time on the Permissions screen. An app does nothing on your behalf that you didn't authorize.
The screen reacts to data
Screen rules are just conversation too: "when an order becomes shipped, lock the record and leave only a Reopen button"; "flag overdue ones in red"; "phone is required when the channel is WhatsApp"; "give me a quick filter for open ones". Dashboards get targets with progress bars, comparison with last month, and a ranking of who buys the most. All computed on the server, identical on the web and on iPhone.
Changed your mind? The app evolves without breaking
Real apps change. In César, editing a published app opens a draft: the live app keeps running untouched while you design the change, and nothing is published without you seeing exactly what will happen. Every version stays in the history, with rollback included. And the golden rule: no publish ever destroys your data — what leaves the screens is kept and restorable.
Your data is never held hostage either: at any moment you can export everything — one CSV per record type, plus your files — in a ZIP.
What does it cost? Less than you'd think
The model is simple: you pay for the intelligence, never for the hosting. The builder conversation and chat questions use your normal César credits, like any conversation. Everything else — the app running, the screens, the automations, the daily alerts, the storage — costs nothing. No price per app, per record or per user.
In other words: building costs a conversation. Using it every day is free.
Five minutes to your first app
- Create your free account;
- Open the panel menu and click Build an app;
- Describe whatever you track today in a spreadsheet, a notebook or your head.
That monster spreadsheet has a retirement date. And the "system I'll have built someday" — you just built it, by yourself, in a conversation.
If your app is for work, it talks to the rest: orders can turn into automatic invoices, support can move to your website and pricing follows the logic of paying for work done, not for a subscription.