BoringSheets

A fast, native spreadsheet for macOS — free for life, and it never connects to the internet.

BoringSheets opens and saves real Excel .xlsx files, with 175+ functions, charts, conditional formatting and filters. The spreadsheet engine — grid renderer, formula parser, calculation/dependency engine, and .xlsx reader/writer — is written from scratch in TypeScript, not wrapped around an existing library. Built on Electron. Mac-first; Windows planned.

• 🆓 Free for life — no subscription, no account, no telemetry.
• 🔌 100% offline — zero network requests; your data never leaves your device.
• 📄 Real .xlsx — formulas, formatting, charts, merges, conditional formatting, named ranges.
• ⚙️ From-scratch engine — tokenizer → parser → AST → evaluator → dependency graph with incremental recalc and cycle detection.

Status: early beta, Mac-first. The build is currently unsigned — on first launch, right-click the app and choose Open.

License: MIT.

Download

⬇ Download for macOS — Apple Silicon

Requires a Mac with Apple Silicon (M1 or later). The beta is unsigned, so on first launch right-click the app → Open, then click Open in the dialog (a one-time step). See all releases ›.

Run it

npm install        # one time
npm run dev        # launch the app with live reload (Mac/Windows)

For a production-style run:

npm run build      # bundle renderer + Electron shell
npm start          # launch the built app

Features

• Grid: canvas-rendered with virtual scrolling, keyboard navigation (arrows, Tab, Enter, Page Up/Down, Home), drag-select ranges, click column/row headers to select, in-cell editing, copy / cut / paste (TSV — interops with real Excel), and undo / redo (full command history).
• Structure: insert / delete rows & columns with automatic formula reference rewriting (references shift, deleted targets become #REF!), drag-to-resize columns/rows (double-click a column border to auto-fit), merge / unmerge cells, and a right-click context menu.
• Fill handle: drag the selection corner to copy values, extend numeric series, or offset formulas (relative refs move, $-anchored refs stay).
• Formulas: full expression parser with Excel operator precedence and 175+ built-in functions — math/trig, statistical (MEDIAN, STDEV, PERCENTILE…), the IFS family (SUMIFS/COUNTIFS/AVERAGEIFS/MAXIFS/MINIFS), text, logical (IF, SWITCH, IFERROR…), lookup (VLOOKUP, XLOOKUP, INDEX/MATCH, CHOOSE…), date/time, information (ISNUMBER, ISBLANK…), and financial (PMT, FV, PV, NPV, IPMT, PPMT…). Incremental recalculation via a dependency graph, with circular-reference detection.
• Cross-sheet references: Sheet2!A1 and 'My Sheet'!A1:B2, with a workbook-wide dependency graph (edits on one sheet recalc dependents on others) and automatic reference rewriting when a sheet is renamed.
• Freeze panes: freeze rows above / columns left of the selection so they stay put while the rest scrolls.
• Sort & filter: sort a selection ascending/descending by the active column (relative formulas re-anchor as rows move), and a Google-Sheets-style filter — a funnel in each column header with sort and a searchable value checklist; multiple columns combine with AND.
• Formatting: font family & size, bold / italic / underline / strikethrough, text & fill color, alignment, text wrap (rows auto-fit), borders, and Excel-style number formats (currency, percent, comma, dates).
• Conditional formatting: cell-value rules (>, <, between, equal, text contains), duplicate/top/bottom, color scales, and data bars.
• Charts: column, bar, line, area, pie, and scatter — floating, draggable, resizable, and live-updating as their source data changes.
• Data validation: list (dropdown) and numeric/text-length rules, enforced on entry, with an in-cell dropdown picker.
• Find & Replace (Cmd/Ctrl+F) with match-case and replace-all.
• Files: open and save real .xlsx workbooks (values, formulas, shared strings, and styles) through native file dialogs; CSV import/export and Export to PDF. Multiple sheets with tabs.

Architecture

electron/        Desktop shell (main + preload, native file dialogs, menus)
src/
  model/         Cell, Sheet, Workbook data model
  engine/        tokenizer → parser → evaluator → functions → calc (recalc) + format
  grid/          Canvas grid renderer + input handling
  ui/            Toolbar
  io/            .xlsx read/write (SpreadsheetML over zip)
  app.ts         Controller wiring engine + grid + UI + files
test/            Headless engine smoke tests

Testing the engine headlessly

npx esbuild test/engine.test.ts --bundle --platform=node --format=cjs --outfile=test/.engine.test.cjs && node test/.engine.test.cjs

Roadmap toward fuller Excel parity

Remaining: pivot tables, the rest of Excel's ~480 functions, persisting charts into the .xlsx file (charts are in-app only for now — formulas, styles, fonts, merges, conditional formatting, data validation, freeze panes, named ranges and notes already round-trip), and richer chart styling.