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FlowSync – Real-Time Collaborative Task Management Platform

Technical Design Document v1.2

Document Status: Final Review
Last Updated: August 25, 2025
Author: [Your Name]
Reviewers: Engineering Team, Product Team

1. Executive Summary

FlowSync is a real-time collaborative task management platform designed to bridge the gap between individual productivity and team coordination. The system enables seamless collaboration through live updates, intelligent notifications, and contextual workflow automation.

1.1 Key Objectives

Real-time Collaboration: Sub-100ms update propagation across all connected clients
Scalability: Support 10,000+ concurrent users with 99.9% uptime
Extensibility: Plugin architecture for third-party integrations
Performance: <200ms API response times at 95th percentile

1.2 Success Metrics

Daily Active Users (DAU): Target 50,000 within 6 months
Real-time sync success rate: >99.95%
User engagement: Average session duration >15 minutes
System availability: 99.9% uptime SLA

2. System Architecture Overview

2.1 High-Level Architecture

┌─────────────────┐ ┌─────────────────┐ ┌─────────────────┐

│ Web Client │ │ Mobile Client │ │ Desktop App │

│ (React SPA) │ │ (React Native)│ │ (Electron) │

└─────────┬───────┘ └─────────┬───────┘ └─────────┬───────┘

│ │ │

└──────────────────────┼──────────────────────┘

│

┌─────────────────────────────────┼─────────────────────────────────┐

│ API Gateway & Load Balancer │

│ (NGINX + HAProxy) │

└─────────────────────────────────┼─────────────────────────────────┘

│

┌──────────────────────┼──────────────────────┐

│ │ │

┌─────────┴───────┐ ┌─────────┴───────┐ ┌─────────┴───────┐

│ Auth Service │ │ Core API │ │ WebSocket │

│ (Node.js) │ │ (Node.js) │ │ Gateway │

└─────────────────┘ └─────────────────┘ └─────────────────┘

│ │ │

└──────────────────────┼──────────────────────┘

│

│ Message Queue │

│ (Redis + Apache Kafka) │

│

┌─────────────────┐ ┌─────────┴───────┐ ┌─────────────────┐

│ PostgreSQL │ │ Redis │ │ Elasticsearch │

│ (Primary DB) │ │ (Cache) │ │ (Search) │

└─────────────────┘ └─────────────────┘ └─────────────────┘

2.2 Technology Stack

Frontend:

React 18 with TypeScript
Redux Toolkit for state management
Socket.IO client for real-time communication
Material-UI for design system
Vite for build tooling

Backend:

Node.js 20 with Express.js
TypeScript for type safety
Socket.IO for WebSocket management
Prisma ORM for database operations
Jest for testing framework

Infrastructure:

PostgreSQL 15 for primary data storage
Redis 7 for caching and session management
Apache Kafka for event streaming
Elasticsearch 8 for full-text search
Docker containerization
AWS ECS for container orchestration

3. Detailed Component Design

3.1 Authentication Service

Responsibility: User authentication, authorization, and session management

Key Features:

JWT-based authentication with refresh tokens
OAuth 2.0 integration (Google, Microsoft, GitHub)
Role-based access control (RBAC)
Multi-factor authentication (MFA)

API Endpoints:

POST /auth/login

POST /auth/register

POST /auth/refresh

POST /auth/logout

GET /auth/profile

PUT /auth/profile

POST /auth/forgot-password

POST /auth/reset-password

Database Schema:

CREATE TABLE users (

id UUID PRIMARY KEY DEFAULT gen_random_uuid(),

email VARCHAR(255) UNIQUE NOT NULL,

password_hash VARCHAR(255),

first_name VARCHAR(100),

last_name VARCHAR(100),

avatar_url TEXT,

role user_role DEFAULT ‘member’,

is_active BOOLEAN DEFAULT true,

email_verified BOOLEAN DEFAULT false,

last_login TIMESTAMPTZ,

created_at TIMESTAMPTZ DEFAULT NOW(),

updated_at TIMESTAMPTZ DEFAULT NOW()

);

3.2 Core API Service

Responsibility: Business logic, data management, and API orchestration

Key Modules:

3.2.1 Project Management

interface Project {

id: string;

description: string;

ownerId: string;

visibility: ‘private’ | ‘team’ | ‘public’;

settings: ProjectSettings;

createdAt: Date;

updatedAt: Date;

}

interface ProjectSettings {

allowGuests: boolean;

defaultTaskPriority: Priority;

notificationSettings: NotificationConfig;

integrations: IntegrationConfig[];

}

3.2.2 Task Management

interface Task {

id: string;

projectId: string;

title: string;

description: string;

assigneeId?: string;

reporterId: string;

status: TaskStatus;

priority: Priority;

labels: string[];

dueDate?: Date;

estimatedHours?: number;

actualHours?: number;

dependencies: string[];

attachments: Attachment[];

comments: Comment[];

customFields: Record<string, any>;

createdAt: Date;

updatedAt: Date;

}

enum TaskStatus {

BACKLOG = ‘backlog’,

TODO = ‘todo’,

IN_PROGRESS = ‘in_progress’,

IN_REVIEW = ‘in_review’,

DONE = ‘done’,

ARCHIVED = ‘archived’

}

enum Priority {

LOW = ‘low’,

MEDIUM = ‘medium’,

HIGH = ‘high’,

CRITICAL = ‘critical’

}

3.3 Real-Time Communication Layer

WebSocket Gateway Architecture:

class WebSocketGateway {

private io: Server;

private redisAdapter: RedisAdapter;

async handleConnection(socket: Socket) {

// Authenticate user

const user = await this.authenticateSocket(socket);

if (!user) {

socket.disconnect();

return;

}

// Join user-specific room

socket.join(`user:${user.id}`);

// Join project rooms based on user permissions

const projects = await this.getUserProjects(user.id);

projects.forEach(project => {

socket.join(`project:${project.id}`);

});

this.setupEventHandlers(socket, user);

}

private setupEventHandlers(socket: Socket, user: User) {

socket.on(‘task:update’, this.handleTaskUpdate);

socket.on(‘task:create’, this.handleTaskCreate);

socket.on(‘task:delete’, this.handleTaskDelete);

socket.on(‘comment:add’, this.handleCommentAdd);

socket.on(‘presence:update’, this.handlePresenceUpdate);

}

Event Types:

interface TaskUpdateEvent {

type: ‘task:update’;

payload: {

taskId: string;

projectId: string;

changes: Partial<Task>;

updatedBy: string;

timestamp: Date;

};

}

interface PresenceEvent {

type: ‘presence:update’;

payload: {

userId: string;

status: ‘online’ | ‘away’ | ‘offline’;

activeProject?: string;

lastSeen: Date;

};

}

4. Data Architecture

4.1 Database Design

Primary Database (PostgreSQL):

— Core entities

CREATE TABLE projects (

id UUID PRIMARY KEY DEFAULT gen_random_uuid(),

name VARCHAR(255) NOT NULL,

description TEXT,

owner_id UUID REFERENCES users(id),

visibility project_visibility DEFAULT ‘private’,

settings JSONB DEFAULT ‘{}’,

created_at TIMESTAMPTZ DEFAULT NOW(),

updated_at TIMESTAMPTZ DEFAULT NOW()

);

CREATE TABLE tasks (

id UUID PRIMARY KEY DEFAULT gen_random_uuid(),

project_id UUID REFERENCES projects(id) ON DELETE CASCADE,

title VARCHAR(500) NOT NULL,

description TEXT,

assignee_id UUID REFERENCES users(id),

reporter_id UUID REFERENCES users(id),

status task_status DEFAULT ‘backlog’,

priority task_priority DEFAULT ‘medium’,

labels TEXT[] DEFAULT ‘{}’,

due_date TIMESTAMPTZ,

estimated_hours INTEGER,

actual_hours INTEGER,

custom_fields JSONB DEFAULT ‘{}’,

created_at TIMESTAMPTZ DEFAULT NOW(),

updated_at TIMESTAMPTZ DEFAULT NOW()

);

CREATE TABLE task_dependencies (

id UUID PRIMARY KEY DEFAULT gen_random_uuid(),

task_id UUID REFERENCES tasks(id) ON DELETE CASCADE,

depends_on_id UUID REFERENCES tasks(id) ON DELETE CASCADE,

created_at TIMESTAMPTZ DEFAULT NOW(),

UNIQUE(task_id, depends_on_id)

);

— Indexes for performance

CREATE INDEX idx_tasks_project_status ON tasks(project_id, status);

CREATE INDEX idx_tasks_assignee ON tasks(assignee_id) WHERE assignee_id IS NOT NULL;

CREATE INDEX idx_tasks_due_date ON tasks(due_date) WHERE due_date IS NOT NULL;

CREATE INDEX idx_tasks_search ON tasks USING GIN(to_tsvector(‘english’, title || ‘ ‘ || description));

4.2 Caching Strategy

Redis Data Structures:

// Session management

const sessionKey = `session:${userId}`;

const sessionData = {

userId: string;

email: string;

role: string;

permissions: string[];

expiresAt: number;

};

// Real-time presence

const presenceKey = `presence:${projectId}`;

const presenceData = {

[userId]: {

status: ‘online’ | ‘away’ | ‘offline’;

lastSeen: Date;

activeTask?: string;

}

};

// Recently accessed projects

const recentProjectsKey = `recent:${userId}`;

// Sorted set with timestamp scores

4.3 Search Architecture

Elasticsearch Index Mapping:

{

“mappings”: {

“properties”: {

“id”: { “type”: “keyword” },

“projectId”: { “type”: “keyword” },

“title”: {

“type”: “text”,

“analyzer”: “standard”,

“fields”: {

“keyword”: { “type”: “keyword” }

}

“description”: {

“type”: “text”,

“analyzer”: “standard”

“assignee”: {

“properties”: {

“id”: { “type”: “keyword” },

“name”: { “type”: “text” }

}

“status”: { “type”: “keyword” },

“priority”: { “type”: “keyword” },

“labels”: { “type”: “keyword” },

“createdAt”: { “type”: “date” },

“updatedAt”: { “type”: “date” }

}

5. Security Architecture

5.1 Authentication & Authorization

JWT Token Structure:

interface JWTPayload {

sub: string; // User ID

email: string;

role: UserRole;

permissions: Permission[];

iat: number;

exp: number;

iss: string;

}

Permission System:

enum Permission {

PROJECT_CREATE = ‘project:create’,

PROJECT_READ = ‘project:read’,

PROJECT_UPDATE = ‘project:update’,

PROJECT_DELETE = ‘project:delete’,

TASK_CREATE = ‘task:create’,

TASK_READ = ‘task:read’,

TASK_UPDATE = ‘task:update’,

TASK_DELETE = ‘task:delete’,

TASK_ASSIGN = ‘task:assign’,

COMMENT_CREATE = ‘comment:create’,

COMMENT_UPDATE = ‘comment:update’,

COMMENT_DELETE = ‘comment:delete’

}

5.2 Data Protection

Encryption:

Data at rest: AES-256 encryption for sensitive fields
Data in transit: TLS 1.3 for all communications
Database connections: SSL/TLS encryption

Input Validation:

const taskUpdateSchema = Joi.object({

title: Joi.string().min(1).max(500).required(),

description: Joi.string().max(10000).allow(”),

assigneeId: Joi.string().uuid().allow(null),

status: Joi.string().valid(…Object.values(TaskStatus)),

priority: Joi.string().valid(…Object.values(Priority)),

dueDate: Joi.date().iso().allow(null),

labels: Joi.array().items(Joi.string().max(50)).max(20)

});

5.3 Rate Limiting

API Rate Limits:

const rateLimitConfig = {

authentication: { windowMs: 15 * 60 * 1000, max: 5 }, // 5 attempts per 15 minutes

api: { windowMs: 15 * 60 * 1000, max: 1000 }, // 1000 requests per 15 minutes

search: { windowMs: 60 * 1000, max: 30 }, // 30 searches per minute

websocket: { windowMs: 1000, max: 100 } // 100 events per second

};

6. Performance & Scalability

6.1 Performance Requirements

Metric	Requirement	Measurement
API Response Time	<200ms (95th percentile)	Application Performance Monitoring
Real-time Event Latency	<100ms	WebSocket ping measurements
Database Query Time	<50ms (95th percentile)	Query performance logs
Search Response Time	<500ms	Elasticsearch metrics
Page Load Time	<2s (initial load)	Web Vitals

6.2 Scaling Strategy

Horizontal Scaling:

Stateless API services behind load balancers
Database read replicas for query distribution
Redis Cluster for cache scaling
WebSocket server scaling with Redis adapter

Vertical Scaling:

Auto-scaling groups based on CPU/memory metrics
Database connection pooling
Redis memory optimization

Database Optimization:

— Partitioning for large tables

CREATE TABLE tasks_2025_q3 PARTITION OF tasks

FOR VALUES FROM (‘2025-07-01’) TO (‘2025-10-01’);

— Materialized views for analytics

CREATE MATERIALIZED VIEW project_stats AS

SELECT

project_id,

COUNT(*) as total_tasks,

COUNT(*) FILTER (WHERE status = ‘done’) as completed_tasks,

AVG(actual_hours) as avg_completion_time

FROM tasks

GROUP BY project_id;

6.3 Monitoring & Observability

Key Metrics:

interface SystemMetrics {

// Performance metrics

responseTime: HistogramMetric;

throughput: CounterMetric;

errorRate: RateMetric;

// Business metrics

activeUsers: GaugeMetric;

tasksCreated: CounterMetric;

projectsCreated: CounterMetric;

// Infrastructure metrics

cpuUsage: GaugeMetric;

memoryUsage: GaugeMetric;

dbConnections: GaugeMetric;

cacheHitRate: RateMetric;

}

Logging Strategy:

interface LogEntry {

timestamp: string;

level: ‘error’ | ‘warn’ | ‘info’ | ‘debug’;

service: string;

traceId: string;

userId?: string;

action: string;

details: Record<string, any>;

duration?: number;

}

7. API Documentation

7.1 REST API Endpoints

Task Management API:

/api/v1/tasks:

get:

summary: Get tasks with filtering and pagination

parameters:

– name: projectId

in: query

required: true

schema:

type: string

format: uuid

– name: status

in: query

schema:

type: array

items:

$ref: ‘#/components/schemas/TaskStatus’

– name: assigneeId

in: query

schema:

type: string

format: uuid

– name: page

in: query

schema:

type: integer

minimum: 1

default: 1

– name: limit

in: query

schema:

type: integer

minimum: 1

maximum: 100

default: 20

responses:

200:

description: Success

content:

application/json:

schema:

type: object

properties:

data:

type: array

items:

$ref: ‘#/components/schemas/Task’

pagination:

$ref: ‘#/components/schemas/PaginationInfo’

post:

summary: Create a new task

requestBody:

required: true

content:

application/json:

schema:

$ref: ‘#/components/schemas/CreateTaskRequest’

responses:

201:

description: Task created successfully

content:

application/json:

schema:

$ref: ‘#/components/schemas/Task’

400:

description: Validation error

403:

description: Insufficient permissions

7.2 WebSocket Events

Event Documentation:

// Client → Server events

interface ClientEvents {

‘task:update’: (data: TaskUpdateData) => void;

‘task:create’: (data: CreateTaskData) => void;

‘comment:add’: (data: AddCommentData) => void;

‘presence:join’: (data: { projectId: string }) => void;

‘presence:leave’: (data: { projectId: string }) => void;

}

// Server → Client events

interface ServerEvents {

‘task:updated’: (data: TaskUpdatedEvent) => void;

‘task:created’: (data: TaskCreatedEvent) => void;

‘comment:added’: (data: CommentAddedEvent) => void;

‘user:presence’: (data: UserPresenceEvent) => void;

‘notification’: (data: NotificationEvent) => void;

}

8. Deployment & DevOps

8.1 Infrastructure as Code

Docker Configuration:

# Production Dockerfile

FROM node:20-alpine AS builder

WORKDIR /app

COPY package*.json ./

RUN npm ci –only=production

FROM node:20-alpine

RUN addgroup -g 1001 -S nodejs && adduser -S nodejs -u 1001

WORKDIR /app

COPY –from=builder /app/node_modules ./node_modules

COPY –chown=nodejs:nodejs . .

USER nodejs

EXPOSE 3000

CMD [“node”, “dist/server.js”]

Kubernetes Deployment:

apiVersion: apps/v1

kind: Deployment

metadata:

spec:

replicas: 3

selector:

matchLabels:

app: flowsync-api

template:

metadata:

labels:

app: flowsync-api

spec:

containers:

– name: api

image: flowsync/api:latest

ports:

– containerPort: 3000

env:

– name: DATABASE_URL

valueFrom:

secretKeyRef:

key: url

resources:

requests:

memory: “256Mi”

cpu: “250m”

limits:

memory: “512Mi”

cpu: “500m”

livenessProbe:

httpGet:

path: /health

port: 3000

initialDelaySeconds: 30

periodSeconds: 10

8.2 CI/CD Pipeline

GitHub Actions Workflow:

on:

push:

branches: [main]

jobs:

test:

runs-on: ubuntu-latest

steps:

– uses: actions/checkout@v3

– uses: actions/setup-node@v3

with:

node-version: ’20’

– run: npm ci

– run: npm run lint

– run: npm run test:unit

– run: npm run test:integration

deploy:

needs: test

runs-on: ubuntu-latest

steps:

– name: Deploy to ECS

run: |

aws ecs update-service \

–cluster production \

–service flowsync-api \

–force-new-deployment

9. Testing Strategy

9.1 Testing Pyramid

Unit Tests (70%):

describe(‘TaskService’, () => {

describe(‘updateTask’, () => {

it(‘should update task and emit real-time event’, async () => {

// Arrange

const mockTask = createMockTask();

const updateData = { title: ‘Updated Title’ };

// Act

const result = await taskService.updateTask(mockTask.id, updateData);

// Assert

expect(result.title).toBe(‘Updated Title’);

expect(eventEmitter.emit).toHaveBeenCalledWith(‘task:updated’, {

taskId: mockTask.id,

changes: updateData

});

Integration Tests (20%):

describe(‘Task API Integration’, () => {

it(‘should create and retrieve task through API’, async () => {

const response = await request(app)

.post(‘/api/v1/tasks’)

.set(‘Authorization’, `Bearer ${authToken}`)

.send(createTaskPayload)

.expect(201);

const taskId = response.body.id;

const getResponse = await request(app)

.get(`/api/v1/tasks/${taskId}`)

.set(‘Authorization’, `Bearer ${authToken}`)

.expect(200);

expect(getResponse.body.title).toBe(createTaskPayload.title);

});

E2E Tests (10%):

describe(‘Task Management Flow’, () => {

it(‘should allow user to create, update, and complete a task’, async () => {

await page.goto(‘/projects/test-project’);

// Create task

await page.click(‘[data-testid=”add-task-button”]’);

await page.fill(‘[data-testid=”task-title”]’, ‘Test Task’);

await page.click(‘[data-testid=”save-task”]’);

// Verify real-time update

await expect(page.locator(‘[data-testid=”task-list”]’)).toContainText(‘Test Task’);

// Update task status

await page.click(‘[data-testid=”task-item”]:has-text(“Test Task”)’);

await page.selectOption(‘[data-testid=”task-status”]’, ‘done’);

await page.click(‘[data-testid=”save-task”]’);

// Verify completion

await expect(page.locator(‘[data-testid=”completed-tasks”]’)).toContainText(‘Test Task’);

});

10. Risk Analysis & Mitigation

10.1 Technical Risks

Risk	Probability	Impact	Mitigation Strategy
WebSocket connection drops	High	Medium	Automatic reconnection with exponential backoff
Database performance degradation	Medium	High	Read replicas, query optimization, monitoring
Third-party API rate limits	Medium	Medium	Caching, queue-based processing, fallback options
Memory leaks in real-time connections	Low	High	Connection lifecycle management, monitoring

10.2 Security Risks

Risk	Probability	Impact	Mitigation Strategy
SQL injection	Low	High	Parameterized queries, ORM usage
XSS attacks	Medium	Medium	Input sanitization, CSP headers
DDoS attacks	Medium	High	Rate limiting, CDN, load balancing
Data breach	Low	Critical	Encryption, access controls, audit logging

10.3 Operational Risks

Risk	Probability	Impact	Mitigation Strategy
Service downtime	Medium	High	Auto-scaling, health checks, circuit breakers
Data loss	Low	Critical	Regular backups, replication, disaster recovery
Performance degradation	High	Medium	Performance monitoring, auto-scaling, caching

11. Future Considerations

11.1 Planned Features (6-month roadmap)

Q4 2025:

Advanced analytics and reporting dashboard
Mobile offline synchronization
Third-party integrations (Slack, Jira, GitHub)
Custom workflow automation

Q1 2026:

AI-powered task prioritization
Advanced time tracking with automatic detection
Multi-workspace support
Advanced permission system with custom roles

11.2 Technical Debt & Improvements

Performance Optimizations:

Implement database sharding for large datasets
Add CDN for static asset delivery
Optimize bundle sizes for faster initial loads

Developer Experience:

GraphQL API layer for flexible data fetching
Comprehensive SDK for third-party developers
Enhanced development tooling and debugging

Infrastructure:

Multi-region deployment for global users
Advanced monitoring with distributed tracing
Automated disaster recovery procedures

12. Conclusion

FlowSync represents a comprehensive solution for real-time collaborative task management, built with modern technologies and scalable architecture principles. The design emphasizes performance, security, and extensibility while maintaining developer productivity and operational simplicity.

The modular architecture allows for independent scaling of components, while the event-driven design ensures consistent real-time updates across all clients. With proper monitoring, testing, and deployment practices, this system is designed to scale from hundreds to hundreds of thousands of users while maintaining high performance and reliability.

Key Success Factors:

Robust real-time synchronization architecture
Comprehensive security and permission system
Scalable infrastructure with proper monitoring
Developer-friendly API design and documentation
Thorough testing strategy across all levels

This technical design document serves as the foundation for implementation and can be referenced throughout the development lifecycle to ensure architectural consistency and quality standards.

Document History:

Version	Date	Author	Changes
1.0	2025-07-15	[Author]	Initial draft
1.1	2025-08-01	[Author]	Added security section, updated API specs
1.2	2025-08-25	[Author]	Performance requirements, deployment details