GridCraft vs Excel: A Pre-Alpha Rust Spreadsheet With 500+ Functions

GridCraft vs Excel is a question about how much of a spreadsheet can be rebuilt from public specifications in a few weeks. The GridCraft repository was created on 7 October 2026, and its README already lists a dependency-graph calculation engine, dynamic arrays, more than 500 worksheet functions, PivotTables and native XLSX. It also calls itself pre-alpha, which is the right label.

What GridCraft is

GridCraft is the spreadsheet in the ArtCraft family, alongside WordCraft and DeckCraft. The Crafting Apps guide places all of them in one picture. It is licensed MIT or Apache-2.0 and runs natively on macOS, Windows, Linux and BSD, and in the browser through WebAssembly.

Microsoft Excel is Microsoft's closed-source spreadsheet, part of Microsoft 365 and sold in other editions, and the reference for formulas, PivotTables, Power Query and VBA that businesses have built on for decades.

The interface and compatibility story

GridCraft reproduces Excel's visible structure: the ribbon, formula bar, Name Box, sheet tabs, fill handle, point-mode formula entry with coloured references, Format Cells, Paste Special, conditional formatting, tables and charts. For someone who lives in Excel, that familiarity is the point.

XLSX is the native format, not an export. The README lists styles, themes, formulas including dynamic arrays, tables, conditional formats, validation, comments, hyperlinks, charts, pictures, sparklines, PivotTables and print settings as round-tripping, plus CSV and TSV. The same README names XLSX fidelity on real-world files as the next task, which is a way of saying the test files so far have been controlled.

Calculation engine

The calculation engine is where a spreadsheet earns trust, and GridCraft's description is ambitious.

• Dependency graph and incremental recalculation, so a change recalculates only what depends on it.
• Dynamic arrays and spilling, the behaviour introduced in recent Excel versions.
• More than 500 worksheet functions plus the lambda family: LET, LAMBDA, MAP, REDUCE, SCAN, BYROW, BYCOL and MAKEARRAY.
• Structured table references and Excel's full number-format language.
• Sorting, AutoFilter, Flash Fill, data validation, outlining and subtotals.
• Copy-on-write workbooks, which make undo snapshots almost free, and a virtualised grid that lays out only what is on screen.

The README puts function coverage at about 93 percent of Excel's worksheet functions and menu coverage at 89 percent of ribbon and menu commands. Weighted by depth, the maintainers estimate about 65 percent of what Excel power users rely on.

What is not there

The roadmap names the next items: signed release builds, XLSX fidelity on real-world files, performance on very large sheets, then slicers, Solver, chart trendlines and a true Page Layout view.

Things the README does not mention at all are also worth separating from things it says are missing: VBA macros, Power Query and Power Pivot are not in the feature list. If a finance team's monthly close runs on macros or data models, GridCraft cannot replace Excel for it.

Collaboration is another gap to check. Excel's co-authoring on shared workbooks is part of the Microsoft 365 service, and GridCraft's README does not describe shared real-time editing.

Automation and agents

Every ribbon button, menu item, dialog, keystroke and gesture is a command that can be run through a JSON control channel, an MCP server or a command-line tool. That includes cell edits and formulas, so an agent can build a model, add a chart and save an XLSX the way a person would. It is the design feature most likely to interest teams building automated reporting.

The command line and agent tools

GridCraft's command-line tool makes the engine unusually easy to test. The README shows evaluating a formula without opening the app, for example an XLOOKUP over two arrays that returns the matching value. Another command runs a sample budget, applies a bold format to a range and writes an XLSX file, and a third prints a range of a workbook as an aligned text table. A command lists every available command with its parameters.

The MCP server exposes tools for reading and writing ranges, setting cells, evaluating formulas, formatting ranges, inserting charts, creating tables, sorting and filtering, and a general execute-command tool that reaches every command in the app. It can run headless or connect to a running window, where the control channel adds real pointer and keyboard input, dialogs and screenshots. That makes it possible for an assistant to build a model, check its numbers and save the file.

The web build opens through the browser's file picker, downloads workbooks on Save, and accepts a sample parameter to open a built-in example.

What to test in your own workbooks

Spreadsheets fail in specific places, so test those directly.

1. Formulas. Open a workbook with your usual functions, including lookups, dates, text handling and any dynamic array formulas, and compare results cell by cell.
2. Number formats. Currency, dates and custom formats are a common source of silent differences.
3. Tables and PivotTables. Check refresh behaviour, grouping and calculated fields.
4. Charts. Compare series, axes, labels and styling with the original.
5. Conditional formatting and validation. Confirm rules and drop-down lists survive a save and reopen.
6. Large sheets. Performance on very large sheets is named as upcoming work.
7. External links, macros and add-ins. These are outside what the README lists.

Save to a new file name each time, and keep the original in Excel until the comparison passes.

The maintainers say they are about 80 percent of the way to a first alpha. That tells you the foundation exists and a stable build is not yet issued.

Cost, licence and privacy

GridCraft is released under MIT or Apache-2.0, and its README states no subscription, no licence server and no telemetry. A spreadsheet that runs locally, offline and without an account suits situations where data cannot leave a machine, such as client financials, health records or confidential models.

Excel can run offline too, but its desktop edition is bound to Microsoft's licensing, and many workbooks end up linked to cloud services. For finance teams the larger question is auditability. An open calculation engine can be inspected and tested against known results, which is useful when a number must be defended. Use that advantage deliberately: compare GridCraft's results with Excel on your own models and keep a record of any differences you find, since the project is still pre-alpha.

How to follow the project

GridCraft publishes a parity file that scores its ribbon and function coverage item by item, and a roadmap file with milestones and estimates. Reading those two files before each evaluation is quicker than testing everything again, because they show what changed since you last looked. Releases appear on the repository's releases page, and bug reports with a real workbook attached are the most useful feedback you can give a project at this stage.

Comparison table

Which one for which job

Keep Excel for workbooks with macros, large data models, complex PivotTable dashboards, or anything shared with partners who expect exact Excel behaviour.

Try GridCraft for personal analysis, for XLSX files with ordinary formulas and charts, or for scripted generation of spreadsheets where an open engine is easier to embed in a pipeline than Excel's automation.

Use LibreOffice when you want a mature, free spreadsheet with years of format handling, Google Sheets when collaboration in a browser matters most, and OnlyOffice when you want to host a browser-based spreadsheet yourself.

The word processor in the same family is covered in WordCraft vs Word, and the presentation app in DeckCraft vs PowerPoint. The free Microsoft Office alternatives guide widens the view, and the productivity category lists more.