Sheet – A Google Sheets-like Spreadsheet - WIP

Sheet is a high-performance, modern web-based spreadsheet application inspired by Google Sheets, built from scratch to deeply understand the architecture, performance, and complexity behind such real-time collaborative tools.

Purpose

This project is a personal learning and upskilling endeavor to explore:

• Spreadsheet engine internals
• Formula evaluation and dependency tracking
• Real-time synchronization patterns
• Frontend performance (100k+ cells)
• Interfacing between Go, Rust, and WebAssembly

Tech Stack

Layer	Technology
Frontend	React (Vite) + TypeScript
Virtualization	React Virtuoso (may later switch to WebGL/OpenGL-based custom renderer)
Backend	Go (REST + WebSocket API)
Formula Engine	Initially in JS (MVP) → Rust (FFI for backend, WebAssembly for frontend)
Database	PostgreSQL
Optimizations	Web Workers, WasmGC, FFI, optimistic updates, dependency graphs

Architecture Overview

Local-First Interaction

• Optimistic UI updates are applied as soon as a cell is changed.
• A Formula Engine runs in the browser to immediately recompute dependent cells.
• Dependency tracking is handled through a local graph, ensuring snappy updates without backend lag.

Backend Responsibilities

• Go server handles:
  • Cell/sheet persistence (PostgreSQL)
  • REST APIs for sheet management
  • FFI callout to Rust formula engine for backend-side verification
  • WebSocket-based multi-user sync (future)

Formula Engine Design

A pluggable interface allows different implementations depending on the environment:

interface FormulaEngine {
  evaluate(cellId: string): ComputedValue;
  recalculate(startCell: string): void;
  setCell(cellId: string, value: RawInput): void;
}

Engine Versions

Environment	Implementation
Frontend	JS (MVP), Wasm (Rust)
Backend	Rust library (FFI via CGO or cbind)

Data Model (PostgreSQL)

-- Sheets
CREATE TABLE sheets (
  id UUID PRIMARY KEY,
  name TEXT,
  owner_id UUID,
  created_at TIMESTAMP,
  updated_at TIMESTAMP
);

-- Cells
CREATE TABLE cells (
  sheet_id UUID REFERENCES sheets(id),
  row INT,
  col INT,
  raw_value TEXT,
  computed_value TEXT,
  type TEXT,
  PRIMARY KEY(sheet_id, row, col)
);

Optionally, JSONB can be used to store sheet content for rapid prototyping.

Roadmap

See TODO.md for detailed implementation phases and milestones.

Future Plans

• Formula engine in WebAssembly (Rust or Go) for near-native performance
• Web Workers to keep evaluation off the main thread
• Real-time sync via WebSocket
• Undo/redo and versioning support
• Sheet export/import (CSV, Excel)

License

MIT — This project is a personal learning exercise. Contributions welcome after MVP stabilization. See LICENSE.md