Spreadsheet

A lightweight, client-only spreadsheet web application. All data persists in the URL hash for instant sharing—no backend required. Optional AES-GCM password protection keeps shared links locked without a server.

Demo Links

• Open example
• Encrypted example
  • Password: A2P7peq8aVixgB2

Screenshots

| Default grid | Password prompt | | ------------------------------------------------ | ------------------------------------------------------ | | | |

| Unlock encrypted link | Raw JSON modal | | ------------------------------ | ------------------------------ | | | |

| Embed generator | QR handoff | | ------------------------------- | ------------------------ | | | |

| Menu | Template gallery | | --------------------------- | ------------------------------------------------ | | | |

| JSON Hash Tool | Formula dependencies | | ---------------------------------------------- | ---------------------------------------------- | | | |

| Live Collaboration | | | ------------------------------------ | --- | | | |

Features

Core Functionality

• Client-only - All state saved in URL hash; no backend required
• Compressed URL State - LZ-String compression keeps share links short
• Instant Sharing - Copy URL to share your spreadsheet with anyone
• Dynamic Grid - Expandable grid; add as many rows/columns as you need
• Arrow Key Navigation - Move the active cell with arrow keys; Shift+Arrow expands selection
• Persistent History - Browser back/forward buttons restore previous states

Text & Cell Styling

• Bold (Ctrl+B) - Apply bold formatting to selected text
• Italic (Ctrl+I) - Apply italic formatting to selected text
• Underline (Ctrl+U) - Apply underline formatting to selected text
• Alignment - Left/center/right alignment per cell or selection
• Font Size - Quick size buttons (Auto, 10-24px)
• Cell Colors - Background and text color pickers
• Style Persistence - Alignment, colors, and sizes saved in the URL
• Sanitized formatting preserved in cell content (B/I/U/STRONG/EM/SPAN with safe styles)

Multi-Cell Selection (Google Sheets Style)

• Click & Drag - Select rectangular ranges by dragging
• Shift+Click - Extend selection from anchor point
• Shift+Arrow - Extend selection with the keyboard
• Visual Feedback - Selected cells highlighted with blue background
• Border Outline - Blue border around selection edges
• Header Highlighting - Row/column headers highlight for selected range
• Hover Highlighting - Row/column hover highlights for quick scanning
• Escape to Clear - Press Escape to deselect
• Selection Stats - Status bar shows count, sum, and average for numeric ranges

Grid Management

• Add Row - Expand grid rows as needed
• Add Column - Expand grid columns as needed
• Row/Column Menus - Header menus for quick insert/delete actions
• Resize Rows/Columns - Drag header handles to adjust sizes
• Clear Spreadsheet - Reset to empty 10x10 grid with confirmation
• Live Grid Size - Display shows current dimensions

Data Import/Export

• CSV Import - Load .csv files from the toolbar
• CSV Export - Download the current grid as spreadsheet.csv
• Excel Export - Download as .xlsx with formulas and basic formatting
• Formula-aware Import - SUM/AVG formulas are preserved; unsupported formulas are imported as text

Tools Menu

• Centralized Actions - Access templates, import/export, sharing, presentation, and collaboration in one place
• Grouped Categories - View, Data & File, Share & Embed, and Advanced sections

Templates Gallery

• Searchable Gallery - Browse built-in templates loaded from templates.json
• One-click Launch - "Use Template" opens a new tab with the template prefilled
• Pre-built Examples - Todo lists, budgets, calculators, and trackers

Presentation Mode

• Row-based Slides - Each non-empty row becomes a slide; first cell is the title
• Keyboard Navigation - Arrow/Page/Space/Home/End keys move between slides
• Quick Exit - Escape closes the presentation overlay
• Visual Formula Widgets - =PROGRESS(), =TAG(), and =RATING() render as visuals

Sharing & Access Control

• Copy Link - One click to copy the compressed URL hash
• Read-only Toggle - Share view-only links that disable editing
• Embed Mode - Generate a read-only iframe snippet with a dedicated embed flag in the URL
• QR Handoff - Show a QR code to continue editing on mobile; warns if the URL is too long
• URL Length Indicator - Live character count with warning/caution/critical thresholds

Live Collaboration (Beta)

• Peer-to-peer via PeerJS - Browser-to-browser sync using WebRTC data channels
• TURN Server Support - Metered.ca TURN servers for NAT traversal; credentials fetched securely via Netlify Function
• 1-to-1 only - One host and one joiner at a time (extra peers are rejected)
• Real-time Sync - Cell edits, formulas, and cursor positions broadcast instantly
• Initial State Transfer - Host sends complete spreadsheet state when joiner connects
• Remote Cursor Presence - See where the other user is editing in real-time
• Automatic Fallback - Falls back to STUN-only if TURN unavailable (~80% success rate)
• Formula Commit Sync - Computed values broadcast when formulas are confirmed
• CSP/network requirement - Allow unpkg.com, *.peerjs.com, and *.metered.live

Password Protection

• One-click lock - Set a password from the toolbar lock button; password never leaves the browser
• AES-GCM 256 + PBKDF2 - 100k iterations with random salt/IV, stored as URL-safe Base64
• ENC-prefixed URLs - Encrypted hashes use ENC:; recipients must unlock via modal
• Optional - Unencrypted links continue to work exactly as before

AI Bridge (Raw JSON)

• Raw Data Modal - View and copy the minified spreadsheet state as JSON for AI edits
• Clipboard Ready - Copy button for quick transfer to ChatGPT/Claude
• Safe Export - Uses sanitized/minified state (only non-default values) for shorter prompts
• JSON Hash Tool - Convert AI-edited JSON into a shareable URL hash, or decode a hash back to JSON

Formula Support

• SUM / AVG Functions - Calculate totals or averages with =SUM(A1:B5) / =AVG(A1:B5)
• Formula Autocomplete - Dropdown suggestions appear when typing =
• Range Selection - Click/drag cells while editing to insert range references
• Live Evaluation - Formulas evaluate on Enter or when leaving the cell
• Recalculation - Dependent formulas update when referenced cells change
• Error Handling - Shows #REF! for invalid ranges, #ERROR! for unknown formulas
• Shareable Formulas - Formulas preserved in URL for sharing

Visual Formula Dependency Tracer

• Trace Logic Overlay - Click the diagram button to draw SVG curves from sources to formulas
• Range Awareness - Ranges render from the center of the referenced block
• Auto Redraw - Updates on edits, scroll, resize, and grid changes

Theme Support