🚀 Velo — Offline-First Project Management Engine

---

📖 Table of Contents

• Executive Summary
• System Architecture
• Architecture Diagrams
• Data Pipeline & Sync Model
• Technical Deep Dive
• Performance & Metrics
• Developer Experience & Setup
• Visuals & Media
• Releases
• Why Velo is Different
• Conclusion
• License

---

🧠 Executive Summary

Modern project management tools assume constant connectivity, which introduces latency, failure points, and degraded UX in real-world mobile environments.

Velo was engineered to solve this problem.

Core Problem

• Network dependency → degraded UX
• High-latency operations (task updates, comments)
• Poor offline support → user frustration
• Sync conflicts → inconsistent state

Solution

Velo implements a local-first architecture where:

• All operations execute instantly on-device
• Changes are stored as operation logs (op-based sync)
• Backend acts as a synchronization and reconciliation layer

Business Impact

• ⚡ Zero-latency interactions (local writes)
• 📡 Resilient offline usage
• 🔄 Eventual consistency across devices
• 📈 Scales from personal use → team collaboration

⬆ Back to Top

---

🧪 Demo & Visuals

📱 Dashboard UI

🎬 Demo Video

See Velo in action — a lightweight, offline-first project management system built for real-world team workflows.

---

⚡ Velo App Demo End-to-end walkthrough of Velo’s core experience — from project creation to task execution and sync. Highlights Project + task management flow Offline-first interactions Sync + state reconciliation Clean, responsive mobile UI

---

⬆️ Back to top

---

🏗️ System Architecture

High-Level Components

Mobile App (React Native)
   ↓
Local Database (Offline-first state)
   ↓
Sync Engine (Op-based queue)
   ↓
Backend API (Fastify)
   ↓
Database (PostgreSQL via Prisma)

Key Architectural Decisions

Decision	Rationale
Offline-first	Eliminates network dependency
Operation-based sync	Enables conflict resolution
Fastify backend	High-performance, low overhead
Prisma ORM	Type-safe schema management
PostgreSQL	Strong consistency + scalability

⬆ Back to Top

---

Architecture Diagrams

Local-first data flow

flowchart TD
  UI[UI] -->|mutate| Repo[Repositories]
  Repo -->|write| SQLite[(SQLite)]
  Repo -->|enqueue| ChangeLog[change_log]
  ChangeLog --> SyncEngine[SyncEngine]
  SyncEngine -->|push| Server[/Sync API/]

Loading

Sync push/pull cycle

sequenceDiagram
  participant Client
  participant Server
  Client->>Server: POST /sync (ops, cursor)
  Server->>Server: apply ops + dedupe + log server_changes
  Server-->>Client: ackOpIds + changes + newCursor
  Client->>Client: mark ops SENT
  Client->>Client: apply changes or create conflicts

Loading

Conflict resolution flow

flowchart TD
  Change[Incoming server change] --> Check{Local pending or newer?}
  Check -- No --> Apply[Apply to local DB]
  Check -- Yes --> Conflict[Create conflict row]
  Conflict --> Resolve[User resolves]
  Resolve --> Enqueue[Enqueue resolution op]

Loading

⬆ Back to Top

---

🔄 Data Pipeline & Sync Model

Core Concept: Operation-Based Sync

Instead of syncing raw state, Velo syncs intent-based operations:

type SyncOperation = {
  id: string
  entity: "task" | "project" | "comment"
  type: "UPSERT" | "DELETE"
  payload: object
  timestamp: number
}

Flow

1. User action → stored locally

2. Operation added to sync queue

3. Sync triggered manually or via settings

4. Backend processes operations:

   • Deduplicates (opId)
   • Applies mutations
   • Generates server changes

5. Client pulls updates via cursor

Example Sync Request

{
  "ops": [
    {
      "id": "op_123",
      "entity": "task",
      "type": "UPSERT",
      "payload": {
        "id": "task_1",
        "title": "Fix login bug"
      }
    }
  ],
  "cursor": "abc123"
}

Example Server Response

{
  "ack": ["op_123"],
  "changes": [
    {
      "entity": "task",
      "type": "UPSERT",
      "payload": {
        "id": "task_2",
        "title": "New task from another device"
      }
    }
  ],
  "nextCursor": "abc124"
}

⬆ Back to Top

---

🔬 Technical Deep Dive

📱 Mobile (React Native)

• React Native 0.76+

• State management: MobX (multi-store architecture)

• Offline storage:

  • MMKV / AsyncStorage

• Navigation: React Navigation

• UI: Custom glassmorphism system

⚙️ Backend

// Core stack
import Fastify from "fastify"
import { PrismaClient } from "@prisma/client"

• Framework: Fastify (low overhead, high throughput)
• ORM: Prisma (type-safe DB access)
• Database: PostgreSQL 15
• Deployment: Docker + Caddy reverse proxy

🧩 Data Modeling

Entities:

• Users
• Workspaces
• Projects
• Tasks
• Comments
• Workspace Members

Relational structure managed via Prisma schema.

🔁 Sync Engine Internals

• Operation queue (client-side)
• Deduplication via opId
• Server change log (serverChange)
• Cursor-based incremental sync

🧠 Conflict Resolution Strategy

• Last-write-wins (timestamp-based)
• Operation idempotency
• Server reconciliation layer

📈 Improving Data Integrity

• Strict schema validation
• Optimistic updates with rollback support
• Sync retries with exponential backoff

⬆ Back to Top

---

📊 Performance & Metrics

Key Metrics

Metric	Value
Local write latency	~0ms (instant)
Sync latency	<300ms typical
Conflict rate	Low (op-based model)
App startup	~1–2s

Testing Strategy

• Unit tests for sync logic
• Integration tests for API routes
• Manual multi-device sync validation

Example Workflow Benchmark

Action	Traditional App	Velo
Create task	Network call	Instant
Edit task	Network call	Instant
Offline usage	Limited	Full

⬆ Back to Top

---

🧑‍💻 Developer Experience & Setup

📦 Installation

git clone https://github.com/yourusername/velo
cd velo
pnpm install

🖥️ Backend Setup

cd backend
cp .env.example .env
pnpm prisma generate
pnpm prisma migrate dev
pnpm dev

📱 Mobile Setup

cd mobile
pnpm start

🐳 Docker (Production)

docker compose -f docker-compose.velo.yml up -d

Environment Configuration

DATABASE_URL=postgresql://user:password@host:5432/db
JWT_SECRET=your_secret

⬆ Back to Top

---

📲 Latest Release

📲 Download APK from the latest Release

---

🚀 Why Velo is Different

1. True Offline-First (Not “Offline Support”)

Most apps degrade offline.

Velo operates fully offline by design.

2. Operation-Based Sync (Not State Sync)

• More scalable
• Conflict-tolerant
• Efficient over low bandwidth

3. Instant UX

• No loading states for core actions
• No blocking network calls

4. Production-Grade Architecture

• Typed backend (Prisma)
• Structured sync pipeline
• Containerized deployment

5. Designed for Real-World Constraints

• Poor connectivity environments
• Mobile-first workflows
• Distributed teams

⬆ Back to Top

---

🔚 Conclusion

Velo demonstrates a production-grade approach to offline-first application design, combining:

• Local-first data modeling
• Robust sync architecture
• High-performance backend systems

It showcases the ability to design systems that are resilient, scalable, and user-centric under real-world constraints.

⬆ Back to Top

---

📄 License

MIT License — feel free to use and adapt.

⬆ Back to Top