Flatland vs.
Excel.
Excel is an untyped grid that computes whatever formulas it's given. Flatland is a typed compiler that refuses to compile invalid models.
Excel · 1985-present · the world's most-deployed numerical surface. · Flatland · 2026 · typed reasoning layer, API-first, metered.
=B7-B8Cell B9 holds a number. The number was computed by subtracting B8 from B7. Whether B7 is revenue or gross profit, whether the subtraction is even semantically valid, is up to the human looking at the sheet.
driver ebitda {
category: "computed",
type: Currency(USD),
formula: gross_profit - opex,
depends_on: [gross_profit, opex]
}
✓ dimensional check: Currency − Currency → Currency
✓ dependencies resolved at compile time
✓ assertion: ebitda > -cash_reserves · passesThe driver has a name, a type, a formula, declared dependencies, and an assertion that constrains the valid output range. The compiler reads all of this before producing a number. If the types don't line up, no number comes out.
Both substrates produce the same number. Only one of them can tell you why, and only one of them refuses to produce it when the math is wrong.
You're building a one-off model with five drivers and three months of life. You need a chart in the next twenty minutes for a board meeting. Your collaborator doesn't use AI and you're working in Office 365 alongside them. You're producing a deliverable that needs Pivot Tables, Power Query, or VBA macros. In all of those cases, Excel is the right tool. We'll still export an Excel you can hand to the auditor; the model lives in Excel, not in our IR.
The model has to outlive the modeler. The model has to be auditable by someone who didn't build it. The model has to be touchable by an AI agent without producing an answer no one can defend. The model has to compile, fail loudly, and tell you exactly which assumption broke.
The model decays.
The compiler doesn't.
Compile your Excel model
into typed IR.
Tell our agent what you'd build in Excel. It produces a typed model with named drivers, assertions, sensitivity analysis, and an Excel export your auditor already recognizes. No replatform. Excel stays the deliverable.