A new open-source spreadsheet called GridCraft is drawing attention among developers and office software users after its project page appeared on GitHub. Built by the ArtCraft team, the application is a clean-room reimplementation of the Microsoft Excel workflow, written entirely in Rust. It runs natively on macOS, Windows, Linux and BSD, and in web browsers through WebAssembly, and it is free to use with no subscription, licence server or telemetry.
The project describes itself as being in alpha. Its maintainers say the core workflow works from start to finish, but depth, fidelity and file compatibility still need work. For readers who rely on spreadsheets every day, the release is worth a closer look, both for what it already offers and for what it says about the state of open alternatives to Excel.
What GridCraft is
GridCraft is a spreadsheet application. Users enter data in cells, write formulas, format tables and build charts, much as they would in Excel. The project's README states that it is a clean-room effort, a term used in software to mean that the code is written from scratch and does not copy the proprietary implementation of another product. The approach allows developers to match a familiar user experience without reusing another company's code.
The interface is designed to feel familiar to Excel users. The project page lists the ribbon, formula bar, Name Box, sheet tabs, keyboard shortcuts, the fill handle, Format Cells, Paste Special and conditional formatting among the supported elements. Formula entry includes a point mode that colours references, a feature many spreadsheet users will recognise from Excel.
The project is also one of a family of creative tools from the ArtCraft team. According to the page, ArtCraft is a community of artists from many disciplines, and GridCraft is one of several free, open-source applications the group publishes, each written from scratch in Rust.
Features aimed at Excel users
According to the project documentation, GridCraft covers a broad range of spreadsheet tasks. The listed capabilities include:
- More than 500 formulas, along with dynamic arrays, LET and LAMBDA, and structured table references.
- PivotTables with field lists, filters, layouts and date grouping.
- Seventeen chart types, a Chart Design tab and a Format pane.
- Accounting formats, cell styles, conditional rules, colour scales and frozen headers.
- Print settings, Page Break Preview, and PDF export and printing.
- Dark mode and an Insert tab for tables, charts, sparklines, pictures, shapes, links and comments.
The developers also point to a sample workbook, a quarterly sales dashboard with a totals row, conditional formatting, sparklines and two live charts, which they say was built entirely with GridCraft commands. Showing a working example of this kind helps potential users judge whether the software can handle the types of files they use at work.
Compatibility with Excel files
File compatibility is central to any Excel alternative, because most people still exchange spreadsheets with colleagues who use Microsoft's software. GridCraft uses the XLSX format as its native format. The project says styles, themes, formulas including dynamic arrays, tables, conditional formats, validation, comments, hyperlinks, charts, pictures, sparklines, PivotTables and print settings should all survive saving and reopening.
The project also supports CSV and TSV files. It can import worksheet data from XLSB and ODS files, though in both cases it uses saved values rather than the original formulas. Those limits matter for anyone who depends on formulas in older or non-XLSX files.
Speed and automation
GridCraft's documentation highlights performance. Its workbooks use copy-on-write, which the project says makes undo snapshots nearly free in terms of cost. The calculation engine recalculates incrementally, and the grid is virtualised, so it lays out only the cells visible on screen.
The project also places weight on automation. Every ribbon button, menu item, dialog, keystroke and mouse gesture is exposed as a command that software agents can run through a JSON control channel, an MCP server or a command-line interface. For developers and power users who script repetitive spreadsheet work, that design could be a significant advantage.
Where the project stands
The maintainers are candid about the limits of the current release. They say GridCraft covers 89 per cent of the Excel ribbon commands in their catalogue and 501 of Excel's 523 worksheet functions. They estimate, weighting features by what Excel users rely on most, that the software is about 50 per cent ready for real work.
The roadmap names the next priorities: fidelity of XLSX files taken from real-world sources, support for very large workbooks, multi-threaded recalculation, deeper chart options, text rendering in every script, and import of the older XLS format. Those gaps suggest that users with complex, heavily formatted or legacy files may still encounter problems.
Platform support is broad but not uniform. On Windows, the desktop app initialises only DirectX 12 by default, because the project says enabling OpenGL can crash some graphics drivers before the window appears. Users who run into this can set the WGPU_BACKEND environment variable as a troubleshooting step. The project says the defaults on macOS, Linux and the web are unchanged.
Why it matters
Spreadsheets are among the most widely used software tools in offices, schools and households, and Excel has long been the default. Open-source alternatives such as LibreOffice Calc already exist, but a new project written in Rust brings a different set of trade-offs, including memory safety and a design built around scripting and AI-driven automation.
Licensing is also part of the appeal. GridCraft is dual-licensed under MIT or Apache-2.0, at the user's option, and the project states that it has no subscription and collects no telemetry. Its documentation also makes clear that it is not affiliated with, sponsored by or endorsed by Microsoft, and that the Excel and Microsoft 365 names are used only to describe compatibility.
Users who want to try the software can download builds for each platform from the latest release on GitHub, which includes checksums for verification. Those who want to help can join the ArtCraft Discord, where the team invites bug reports and feature requests.
Outlook
GridCraft is early work, and the team's own estimates suggest it is not yet a full replacement for Excel in most professional settings. Still, the combination of a familiar interface, a clean-room codebase, broad function coverage and automation hooks gives it a clear identity. Over the coming releases, progress on XLSX fidelity and large-file performance will be the key signals of whether it can move from promising alpha to dependable everyday tool.
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