The AI-Native Spreadsheet Engine

Open source. Excel-compatible. Talk to the Agent in plain language — or write the formula yourself. Excel, Python, SQL, all in cells you can see and edit. Built for billions of rows.

We'll email you when Expanse is ready. No spam.

Q4 Forecast.xlsx
You
> Forecast Q3 revenue from the monthly history in column A

Expanse
I see 48 months of revenue in A1:A48 with mild seasonality.
Fitting an ARIMA(2,1,1) model in a Python cell and writing the
forecast to B49:B54.

  ✓ B49:B54   Sandboxed Python in cells
  ✓ Forecast  $284k → $312k   (+10% over Q3)

You
> Plot it against history

Expanse
Inserted a line chart spanning D2:K22 with two series:

  ✓ Historical   blue,    A1:A48
  ✓ Forecast     orange,  B49:B54

Click the chart to tune colors, axes, or annotations.

The Grid you know.
The Agent you didn't.

Spreadsheets are the most-used programming language on Earth — but they've barely changed in forty years. Excel locks you in. Google Sheets caps your rows. Notebooks scare your finance team. The right tool for any given task usually isn't a tool at all — it's a workbook that nobody else can run.

Expanse is a spreadsheet you already know how to use. The Grid is a Grid — cells, formulas, ranges, charts. What's new is the Agent. Tell it what you want in plain language ("forecast Q3 revenue", "find duplicates in column B", "model the new pricing tier") and it writes the formula into cells you can read, edit, and audit yourself.

Behind every cell are 345 Excel functions, a sandboxed Python runtime with numpy/pandas/polars, and SQL at terabyte scale. Your workbook stays a single .xlsx — round-trippable into Excel, version-controllable in git.

Why Expanse

04 / Completely Free open source · forever
03 / Any Device mac · linux · windows
02 / Web — Coming Soon browser-native
01 / Real-Time Collaboration multiplayer · cursors · history

Build your own financial model.

Replaces

Microsoft ExcelGoogle SheetsLibreOffice Calc

Ask the Agent for what you want — or write the formula yourself if you'd rather. Excel for the model your CFO can read. Python for the analysis your data scientist already wrote. SQL for the warehouse you can't fit in memory. AI for "I'll know it when I see it."

Stop bouncing between tools. Stop exporting CSVs back and forth. One workbook, one dependency graph, four ways to express what comes next.

A1     Jan 2024
A2:A12 Feb 2024 ... Dec 2024
B1:B12 124,000   128,500   135,200   ...   197,800

B13    =SUM(B1:B12)
B14    =AVERAGE(B1:B12)
B15    =NPV(0.08, B1:B12) - Investment
B16    =IRR(B1:B12) * 100
B17    =PMT(0.05/12, 360, -300000)
B18    =VLOOKUP(D1, Products!A:E, 5, FALSE)
B19    =SUMIFS(Revenue, Region, "EMEA", Quarter, "Q4")
B20    =FORECAST.ETS(D1, B1:B12, A1:A12)
B21    =IFS(B19 > 1e6, "high", B19 > 5e5, "med", TRUE, "low")

What you get

Real-time collaboration

Multiplayer cells, cursors, and history.

Any device

Native apps for Mac, Linux, and Windows.

Web — coming soon

Open in any browser, no install needed.

Completely free

Open source. No paywalls. Forever.