Version the rules.
Not the “source code”.
A business rule, like how a late fee is charged, usually gets written down four times: in the database, in the code, in a spreadsheet and in the docs. Version control then tracks four piles of text, and when the rule changes someone has to find every copy. Sooner or later one is missed.
Here the rule is written once, and the rule is what gets the version. The code, the spreadsheet and the docs are rebuilt from it every time, so there is nothing else to keep in step.
Determined by priority: the monthly rent times the late fee percent if the days late is greater than the grace days; in all other cases, 0.IF(((D2 > F2)=TRUE), C2 * G2, 0)Move the grace-period slider and watch version one become version two.
A slider, a deliberate mistake typed straight into the rulebook, a fix made in Excel, and back to version one. Every copy follows along by itself. Watch on YouTube
The same card at its Enterprise level: a version named by a fingerprint of the rules, every fee with its derivation, the rule built four ways, and eight file formats in and out. Watch on YouTube
Move the grace-period slider. A rule's numbers are part of the rules, so version one becomes version two and every line is rebuilt.
Add a day to a lease. One fee is recomputed, but no rule changed, so the version does not change either.
Edit the rules in Excel or YAML and drop the file back. If the rules match, so does the version. Put everything back and it reads v1 again.
One rulebook in the middle. Everything else is built from it.
You describe your business once, as tables, fields and calculations. Seeds add what you need around it, tools generate the code, and hosting puts it online. Change a rule and everything rebuilds.
Free to try. Add what you need.
This is a project, drawn exactly as you will see it in the app. Open the rows.
- ◆The core rulebook
Every project has one. It holds your model, and every tool reads it. Each tool's path to it is worked out for you.
- BESeeds
Packages you add: an import, a database, an app. Some seeds are free, others charge. A seed can include other seeds and the tools they bring.
- ⚙Tools
Each one turns the rulebook into something: SQL, an API, a workbook, docs.
- ▲Hosting
Press Run app and the project is built and put online as a live preview. Run it again whenever you need it.
- Licenses
Any seed or tool may carry one: declared, tracked or enforced. A license governs future runs only. What you have generated is yours.
We turn what you already know into working software — at any scale.
Drop a rulebook, get a working repository back — that is the whole of it, and the film is fifteen minutes of it actually happening.
The full walkthrough · Drop Your Rulebook Here · 15 min
The rulebook is the only thing anyone writes or edits. Change a rule, and the database, API, app, docs and tests all follow. They cannot drift, because they were never independently written in the first place.
A bigger rulebook still costs more to build than a smaller one — it just doesn't scale the way hand-written code does, where every added table means another round of labor. Generation is closer to a print run than a construction project: the cost follows the rulebook, not the hours a person spends typing it.
A solo builder gets the identical core mechanism for $0, today. That is not a loss leader — it is the proof. You can watch the exact machine that builds an enterprise system build your own project first.
A very small project running in the page: move a rule and every generated line is rebuilt by the real tool.
Read the detailsThe docs →Rulebooks, seeds, tools, builds and the CLI, written down step by step.
Pick a starting pointSeeds →Everything you can add to a project, with its price and license shown before you add it.