Full Stack / FrontendYEAR: 2025ROLE: Full Stack Engineer

Real-Time WebSocket Canvas

A collaborative drawing whiteboard application built with WebSockets and HTML5 Canvas allowing real-time multi-user cursor sync and room sessions.

// TECHNOLOGIES USED

TypeScriptNext.jsReactNode.jsWebSocketsHTML5 CanvasTailwind CSS

Source Code ↗

ws://canvas-cluster/room-809

3 PEERS CONNECTED

Protocol: WebSocketsEngine: HTML5 Canvas

// 01. OVERVIEW

Project Overview

An event-driven collaborative canvas built to explore WebSocket binary and JSON message streaming without relying on heavy third-party SaaS services.

// 02. PROBLEM & SOLUTION

The Problem

Real-time canvas drawing requires broadcasting coordinates with minimal network bandwidth usage to prevent stutter across concurrent clients.

The Solution

Designed a lightweight WebSocket message protocol that batches drawing path points before broadcasting to active room subscribers.

// 03. SYSTEM ARCHITECTURE

System Design & Data Flow

// SYSTEM ARCHITECTURE FLOWHTML/CSS Rendered Flow

LAYER 01

User Canvas Client (React)

LAYER 02

WebSocket Client Connection

LAYER 03

Node.js WSS Server (Room Hub)

LAYER 04

Broadcast Broadcast Pipeline

Architectural Highlights

HTML5 Canvas rendering engine with double-buffering logic
Node.js WebSocket server managing active room subscriptions
Next.js client interface with responsive toolbar and color pickers

// 04. KEY FEATURES

Core Functionality & Capabilities

Low-latency vector path broadcasting over WebSockets

Room-based drawing session isolation

Undo/Redo drawing history stack

Responsive HTML5 Canvas rendering for mobile and desktop screens

// 05. TECHNICAL CHALLENGES

Obstacles & Engineering Solutions

Challenge #1: Synchronizing state when new users join an active drawing session.

Solution: Implemented an in-memory session canvas snapshot generator on the server that broadcasts current state upon client handshake.

// 06. ENGINEERING DECISIONS

Trade-offs & Design Rationale

Selected native WebSockets over heavy abstractions to understand low-level connection lifecycles and heartbeat reconnect logic

// 07. LEARNINGS & TAKEAWAYS

Personal Growth & Technical Insights