GridCraft is an open-source spreadsheet written in Rust that works the way Excel does: the ribbon, the formula bar, Excel formulas and real .xlsx files. Here it runs in a browser tab, and your workbooks never leave your computer.
The Home, Insert, Page Layout, Formulas, Data, Review and View tabs, the Name Box, sheet tabs, the fill handle and the keyboard shortcuts are where you expect them. Under them is a calculation engine that recalculates only what changed.
501 of Excel’s 523 worksheet functions, dynamic arrays that spill, LET and LAMBDA with MAP, REDUCE, SCAN, BYROW and BYCOL, and structured table references. Click cells while you type a formula and each reference gets its own color, as in Excel.
Screenshot from the GridCraft project
Excel’s full number-format language, cell styles, borders, Format Cells and Paste Special. Conditional formatting covers highlight rules, data bars, color scales and icon sets. Freeze the header row, sort, filter, add data validation and Flash Fill a column from an example.
Screenshot from the GridCraft project
Pick fields for Rows, Columns, Values and Filters in the PivotTable Fields pane, group dates, and show values as a percentage of the total or as a running total. PivotTables are saved to and read from XLSX files.
Screenshot from the GridCraft project
Seventeen chart types with a Chart Design tab and a Format pane. Select a chart and its source data is outlined in the sheet. Sparklines fit a trend into a single cell.
Screenshot from the GridCraft project
Switch the whole interface to dark. The Insert tab adds tables, charts, sparklines, pictures (PNG and JPEG from your disk), shapes, text boxes, links and comments.
Screenshot from the GridCraft project
Page Break Preview, print areas, print titles, margins and headers and footers are kept in the file. In the browser, export a sheet as a PDF download; printing to a printer needs the desktop app.
Screenshot from the GridCraft projectOpen the Spreadsheet AI panel beside the grid, paste an OpenAI, Google Gemini or OpenRouter key, and ask in plain words. Formulas come with a Copy button: click a cell and paste. Tables open in GridCraft as a new workbook.
Requests go from your browser to the provider. We never see your key, your workbook or the answers, and we add no markup.
How the AI panel worksThe spreadsheet is the official web build, byte for byte. Around it we add a few things the bare build doesn’t have.
Each new GridCraft release is checked against its published SHA-256 checksum and deployed here. You are on v0.5.0.
Formulas, workbook answers and tables from OpenAI, Gemini or OpenRouter models, straight from the browser.
Open GridCraft with its own samples loaded:Quarterly Sales Dashboard, Household Budget, Gradebook.
No account, no upload, no telemetry in the app. Close the tab and nothing of yours is left on a server.
GridCraft is in alpha. Keep a copy of the original file, check important results, and save before closing the tab: the browser version has no autosave. See the guides on opening XLSX files and converting CSV to XLSX.
Yes. The spreadsheet is free and open source, with no account, no subscription and no limits set by us. The optional Spreadsheet AI panel runs on your own AI provider key, so any AI usage is billed by your provider, not by us.
No. GridCraft runs inside your browser with WebAssembly. Files open from your disk through the file picker or a drag and drop, and Save hands the workbook back as a download. The one exception is the Spreadsheet AI panel: when you attach a workbook to a question, its contents go straight to the AI provider whose key you entered.
Excel workbooks (.xlsx, and .xlsm without its macros), CSV, TSV and tab-delimited text. Binary .xlsb and OpenDocument .ods files open as values only, using the results saved in the file instead of the formulas. Old .xls files and password-protected workbooks are not supported yet, and very large workbooks (around 100 MB) fail to open.
No. The browser version has no autosave: the AutoSave switch in GridCraft’s title bar only works for workbooks saved to a file on disk, which a browser tab doesn’t have. Use Save (Ctrl/⌘+S), which downloads an .xlsx file, before you close the tab. This page asks before you leave once you have edited.
Not in the browser. Save always downloads an .xlsx workbook; Export as CSV and Export as Web Page need a file path, which only the desktop app has. You can open the .xlsx in the desktop app, or convert it with gridcraft-cli, to get CSV.
Not in the browser version. It bundles no fonts for Chinese, Japanese, Korean, Arabic, Hebrew or Thai, so text in those scripts shows as empty boxes. The desktop app falls back to your system fonts for Chinese, Japanese, Korean, Thai and Hebrew text (Arabic is not shaped yet).
Yes, as text. Copy puts the cells on your clipboard as text and, where the browser allows it, as a formatted table. Paste (Ctrl/⌘+V) fills cells from tab-separated text copied from another spreadsheet, and pasted text that starts with = becomes a formula.
Not yet, and its developers say so. GridCraft is an independent, clean-room project in alpha. By their own estimate it is about 50% ready for real work: it covers 89% of the Excel ribbon commands in their catalog and 501 of Excel’s 523 functions, but there are no VBA macros, no .xls files and no Power Query, and charts are simpler than Excel’s.
Free, private, and already loaded on your next visit.