storytold/gridcraft

Spreadsheets and data; an open-source, clean-room reimplementation of Microsoft Excel, rebuilt in pure Rust.

A fast, open-source, clean-room take on the Excel workflow. It runs natively on macOS, Windows, Linux and BSD, and in the browser via WebAssembly.
By the ArtCraft team.

GridCraft on getartcraft.com · ArtCraft · All Crafting Apps

_{Quarterly Sales Dashboard: a table with a totals row, conditional formatting, sparklines and two live charts — built entirely from GridCraft commands (File → New → Sample).}

A look around · Why GridCraft · Quick start · For agents · Architecture · Roadmap · The Crafting Apps · License and credits

Formatting. Accounting formats, cell styles, conditional rules and colour scales, frozen headers and a bar chart.	Formulas. 500+ functions, dynamic arrays, LET and LAMBDA, structured table references.
Dark mode and the Insert tab: tables, charts, sparklines, pictures, shapes, links and comments.	PivotTables. Field list, filters, layouts, date grouping and show-values-as, saved to and read from XLSX.
Charts. Seventeen chart types, Chart Design tab and a Format pane; selecting a chart outlines its source data.	Page Break Preview, print settings, and PDF export and printing.

• Familiar. Excel's ribbon, formula bar, Name Box, sheet tabs, keyboard shortcuts, fill handle, point-mode formula entry with coloured references, Format Cells, Paste Special, conditional formatting, tables, charts and more. If you know Excel, you already know GridCraft.
• Compatible. XLSX is the native format: styles, themes, formulas (including dynamic arrays), tables, conditional formats, validation, comments, hyperlinks, charts, pictures, sparklines, PivotTables and print settings round-trip. CSV and TSV too. Excel 97-2003 .xls workbooks open with their values, formulas and number formats (formatting and objects not yet). XLSB worksheet data can be imported, using saved values instead of formulas. ODS worksheet data can be imported, using saved values instead of formulas. Static pictures can live inside cells, fitting their size and moving with the data.
• Capable. A dependency-graph calculation engine with dynamic arrays and spilling, 500+ worksheet functions plus LET, LAMBDA, MAP, REDUCE, SCAN, BYROW, BYCOL and MAKEARRAY, structured table references, Excel's full number-format language, sort and AutoFilter, Flash Fill, data validation, outlining and subtotals.
• Fast. Copy-on-write workbooks (undo snapshots are nearly free), incremental recalculation, and a virtualised grid that only lays out what's on screen.
• Agent-native. Every ribbon button, menu item, dialog, keystroke and mouse gesture is a command that agents can run over a JSON control channel, an MCP server, or the CLI.
• Everywhere. One Rust codebase for desktop and the web. No subscription, no licence server, no telemetry.

cargo run --release -p gridcraft                              # desktop app
cargo run --release -p gridcraft -- --sample sales            # open a sample (sales, budget, grades)
cargo run --release -p gridcraft -- book.xlsx                 # open a workbook
cargo run --release -p gridcraft -- --sample sales --control 7979   # + JSON control channel
cargo xtask ci                                                 # fmt, clippy, tests, assets, layering, wasm

Choose Español under View → Interface language for Spanish formula names, decimal commas, and semicolon arguments. Workbooks, clipboard exchange, and programmatic APIs retain canonical English syntax.

cd apps/gridcraft-web && trunk build --release     # → dist/web (serve it with any static server)
cd apps/gridcraft-web && trunk serve --release     # http://127.0.0.1:8771  (?sample=sales opens a sample)

You need trunk and the wasm32-unknown-unknown target. Open uses the browser's file picker (dropping files works too) and Save downloads the workbook.

Press and release left Alt on Windows/Linux/BSD, or press F10 on any platform, then type a sequence below one key at a time. Keytips appear on the supported Home controls and menu items. On macOS, use F10 (Fn+F10 if required by your keyboard); Option remains available for entering accented characters.

In Paste Special, T/V/F/C select formats/values/formulas/comments, and E toggles Transpose. Enter applies the selected options; Escape cancels the dialog. These letters also work with Alt held on Windows/Linux/BSD.

Escape backs out one keytip level; Alt/F10 again exits keytips. Clicking, scrolling, or switching windows cancels navigation. Access keys do not start while editing text or using another dialog. This is initial support for these Home and legacy paths; other ribbon commands and full mouse-free navigation remain to be implemented. Browsers or desktop environments may reserve Alt/F10 for their own menus.

The desktop app writes its log to standard error and to gridcraft.log in the logs folder next to its settings: ~/.config/gridcraft/logs on Linux and BSD ($XDG_CONFIG_HOME/gridcraft/logs when set), ~/Library/Application Support/GridCraft/logs on macOS and %APPDATA%\GridCraft\logs on Windows. Each start moves the previous log to gridcraft.1.log and that one to gridcraft.2.log, so the log of a run that crashed survives the next start; attach them to a bug report. A log file stops growing at 16 MiB. By default GridCraft's own crates log at info and everything else at warn; RUST_LOG replaces that with env_logger-style directives, e.g. RUST_LOG=debug or RUST_LOG=warn,gridcraft_engine=debug (a trailing * matches a prefix: gridcraft*=debug). Runs with GRIDCRAFT_NO_PREFS set (no saved settings) log to standard error only.

claude mcp add gridcraft -- gridcraft-cli mcp                 # headless MCP server
gridcraft-cli mcp --connect 7979                               # MCP bridged to a running window
gridcraft-cli eval '=XLOOKUP("b",{"a","b"},{1,2})'             # → 2
gridcraft-cli run --sample budget --cmd 'home.bold={"range":"B4:F4"}' --out budget.xlsx
gridcraft-cli cat budget.xlsx --range B4:F15                   # aligned text table
gridcraft-cli commands --search chart                          # every command and its params

The MCP server offers tools such as read_range, write_range, set_cell, evaluate_formula, format_range, insert_chart, create_table, sort_range, filter and execute_command (which reaches every one of GridCraft's commands). The desktop app's control channel adds real pointer and keyboard input, dialogs and screenshots. See docs/mcp.md, docs/cli.md and docs/control-protocol.md.

GridCraft is an engine-first Cargo workspace with enforced layering (cargo xtask layers). The egui frontend is a separate crate, so the UI can be swapped without touching the engine.

• Contributor and agent rules (clean-room, asset policy, never-crash, quality gates): AGENTS.md
• Bundled assets: each one is listed with its licence in ATTRIBUTION.md
• Releases: signed macOS, Windows, Linux, BSD and web builds; see docs/releasing.md

GridCraft is in alpha: the core workflow works end to end, but depth, fidelity and file compatibility are still rough. It covers 89% of the Excel ribbon commands in our catalog (docs/parity-checklist.md) and 513 of Excel's 523 worksheet functions (docs/function-parity.md); weighted by what Excel users rely on, we estimate it is about 50% ready for real work. Next up: XLSX fidelity on real-world files, very large workbooks and multi-threaded recalc, chart depth, text in every script, and .xls import. Stage, numbers and estimates are in ROADMAP.md; the ranked work list is docs/gaps.md.

Download GridCraft from GitHub: the latest release has every build listed below, and all releases has earlier versions and their notes. <ver> in the file names is the version number, and SHA256SUMS.txt lists a checksum for every file.

Installers and executables are code-signed. The MSI installer offers an optional desktop shortcut (unchecked on a new installation).

If the app doesn't open on Windows: the desktop app initializes only DirectX 12 by default. Letting wgpu also create an OpenGL instance can crash some graphics drivers (AMD's atio6axx.dll) before the window appears, so the app would flash in Task Manager and quit. WGPU_BACKEND overrides the default for troubleshooting (for example dx12 or vulkan). In PowerShell, from the folder containing the executable:

$env:WGPU_BACKEND = "vulkan"
& .\gridcraft.exe
Remove-Item Env:WGPU_BACKEND                     # restore the default for later launches

An explicit gl override can bring the driver crash back on affected systems, and vulkan can bring back a crash in some Intel UHD Graphics drivers (igvk64.dll, #120). The macOS, Linux and web backend defaults are unchanged.

If the app is slow on an older Windows PC, or DirectX 12 can't start: when DirectX 12 finds no graphics card with a driver for it, it only offers Microsoft's software renderer, which draws every frame on the processor. In that case GridCraft uses OpenGL instead, without setting anything; if the first renderer fails to start, it tries the other one once. The log file records the choice (lines starting with graphics:). WGPU_BACKEND still overrides it (and then nothing else is tried), e.g. $env:WGPU_BACKEND = "gl" or "dx12".

DirectX 12 shaders are compiled with FXC, which is part of Windows, so no dxcompiler.dll or dxil.dll is needed, and a copy another program put on PATH can no longer stop the app at start ("Parent device is lost", #339). $env:WGPU_DX12_COMPILER = "dxc" (or "auto") selects wgpu's DXC handling again for troubleshooting.

GridCraft is one of the Crafting Apps: free, open-source creative tools from the ArtCraft team, each written from scratch in Rust and each able to stand on its own.

	App	What it's for	Code	Learn more
	PhotoCraft	Image editing: layers, masks, type and real PSD files	GitHub	Website
	VectorCraft	Vector illustration	GitHub	Website
	FilmCraft	Video editing, color and sound	GitHub	Website
	LightCraft	Photo library and raw development	GitHub	Website
	PdfCraft	Reading, organizing and protecting PDFs	GitHub	Website
	EffectCraft	Motion graphics and visual effects	GitHub	Website
	DesignCraft	Page layout and publishing	GitHub	Website
	GridCraft	Spreadsheets and data · you are here	GitHub	Website

And ArtCraft itself, our AI image and video studio for artists who want real control.

Our Discord is where artists of every kind hang out: people who paint, shoot, draw, cut film, set type, and people still figuring out what they like to make. Share what you're working on, ask for help, tell us what's broken, or tell us what you wish these tools could do. Whatever your medium and however long you've been at it, you're welcome here.

discord.gg/artcraft · getartcraft.com · The Crafting Apps · GridCraft

GridCraft is dual-licensed under MIT or Apache-2.0, at your option. Copyright (c) 2026 ArtCraft Team and the GridCraft contributors. Required notices are in NOTICE.

Bundled fonts, icons, images and other assets keep their own open licenses; each one is listed with its author, source and license in ATTRIBUTION.md.

All UI icons are drawn in code and are original; the sample workbooks and every screenshot in this README were made with GridCraft itself. GridCraft bundles no fonts: it uses the fonts installed on your system.

The ArtCraft name, wordmark and logos in docs/brand/ are trademarks of the ArtCraft Team and are not covered by this license. They may be used only unmodified, and only as part of this repository and GridCraft, under docs/brand/LICENSE-brand.txt. Forks and modified versions must remove them.

_{Microsoft, Excel and Microsoft 365 are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries. GridCraft is an independent, open-source project and is not affiliated with, sponsored by or endorsed by Microsoft Corporation; these names are used only to describe the workflows it is compatible with.}

_{Made by the ArtCraft team and community.}