Introduction

Roblox Studio is the integrated development environment (IDE) used by millions of creators to build games and experiences for the Roblox platform. It provides tools for 3D modeling, scripting, asset management, testing, and publishing. Key features include real-time collaboration (Team Create), version control, plugin system, and seamless integration with the Roblox platform.

This post provides a detailed walkthrough of designing Roblox Studio, covering IDE architecture, real-time collaboration, asset management, version control, plugin system, and integration with the Roblox platform. This is a common system design interview question that tests your understanding of developer tools, IDEs, real-time collaboration, version control, and distributed systems.

Table of Contents

  1. Problem Statement
  2. Requirements
  3. Capacity Estimation
  4. Core Entities
  5. API
  6. Data Flow
  7. Database Design
  8. High-Level Design
  9. Deep Dive
  10. Summary

Problem Statement

Design Roblox Studio, a creator IDE for building Roblox experiences with the following features:

  1. 3D scene editor with drag-and-drop
  2. Script editor with syntax highlighting
  3. Real-time collaboration (Team Create) - multiple creators editing simultaneously
  4. Asset management and library
  5. Version control and history
  6. Plugin system for extensibility
  7. Testing and debugging tools
  8. Publishing to Roblox platform
  9. Cloud sync for projects
  10. Offline editing support

Scale Requirements:

  • 10 million+ creators
  • 1 million+ active Studio sessions daily
  • 100,000+ concurrent Team Create sessions
  • Petabytes of project data
  • Must support real-time collaboration with < 100ms latency
  • Must handle large projects (GB+ sizes)
  • Cross-platform support (Windows, Mac)

Requirements

Functional Requirements

Core Features:

  1. 3D Scene Editor: Visual editing of 3D scenes, objects, properties
  2. Script Editor: Code editing with syntax highlighting, autocomplete
  3. Team Create: Real-time collaborative editing
  4. Asset Management: Import, organize, and manage assets
  5. Version Control: Track changes, history, rollback
  6. Plugin System: Extend Studio with plugins
  7. Testing Tools: Test experiences locally before publishing
  8. Publishing: Publish experiences to Roblox platform
  9. Cloud Sync: Sync projects across devices
  10. Offline Mode: Work offline, sync when online

Out of Scope:

  • Game engine rendering (focus on editor)
  • Payment processing (assume existing)
  • User authentication (assume existing)
  • Mobile app (focus on desktop)

Non-Functional Requirements

  1. Availability: 99.9% uptime
  2. Reliability: No data loss, consistent collaboration state
  3. Performance:
    • Collaboration updates: < 100ms latency
    • Asset loading: < 2 seconds
    • Project sync: < 5 seconds for small projects
    • Editor responsiveness: < 50ms for UI interactions
  4. Scalability: Handle 100K+ concurrent Team Create sessions
  5. Consistency: Strong consistency for collaboration, eventual for sync
  6. Offline Support: Full functionality offline with sync

Capacity Estimation

Traffic Estimates

  • Total Creators: 10 million
  • Daily Active Creators: 1 million
  • Active Studio Sessions: 1 million per day
  • Team Create Sessions: 100,000 concurrent
  • Collaboration Updates: 10 million per second (peak)
  • Asset Uploads: 10 million per day
  • Project Syncs: 5 million per day
  • Average Team Size: 3-5 creators per project

Storage Estimates

Project Data:

  • 50M projects × 100MB average = 5PB
  • Project files, assets, scripts, configurations

Asset Library:

  • 1B assets × 5MB average = 5PB
  • Models, textures, sounds, animations

Version History:

  • 5M versions/day × 10MB = 50TB/day
  • 30-day retention: ~1.5PB
  • 1-year archive: ~18PB

Collaboration State:

  • 100K sessions × 1MB = 100GB (in-memory)
  • Collaboration logs: 10M updates/day × 1KB = 10GB/day

Total Storage: ~25PB

Bandwidth Estimates

Normal Traffic:

  • 100K Team Create sessions × 10KB/s = 1GB/s = 8Gbps
  • Collaboration updates, state sync

Peak Traffic:

  • 100K sessions × 50KB/s = 5GB/s = 40Gbps

Asset Downloads:

  • 10M uploads/day × 5MB = 50TB/day = ~580GB/s = ~4.6Tbps

Project Syncs:

  • 5M syncs/day × 100MB = 500TB/day = ~5.8GB/s = ~46Gbps

Total Peak: ~4.6Tbps

Core Entities

Project

  • project_id (UUID)
  • creator_id (user_id)
  • project_name (VARCHAR)
  • description (TEXT)
  • project_data (JSON/BLOB, scene hierarchy, scripts)
  • version (INT)
  • is_published (BOOLEAN)
  • published_experience_id (UUID, optional)
  • created_at (TIMESTAMP)
  • updated_at (TIMESTAMP)
  • last_synced_at (TIMESTAMP)

Team Create Session

  • session_id (UUID)
  • project_id (UUID)
  • host_user_id (user_id)
  • session_status (active, paused, closed)
  • max_collaborators (INT)
  • current_collaborators (JSON array)
  • created_at (TIMESTAMP)
  • updated_at (TIMESTAMP)

Collaboration Event

  • event_id (UUID)
  • session_id (UUID)
  • user_id (UUID)
  • event_type (create, update, delete, move)
  • target_object (VARCHAR, object ID/path)
  • event_data (JSON)
  • timestamp (TIMESTAMP)
  • sequence_number (INT)

Asset

  • asset_id (UUID)
  • creator_id (user_id)
  • asset_type (model, texture, sound, script, etc.)
  • asset_name (VARCHAR)
  • asset_url (VARCHAR)
  • file_size (BIGINT)
  • tags (JSON array)
  • is_public (BOOLEAN)
  • created_at (TIMESTAMP)

Project Version

  • version_id (UUID)
  • project_id (UUID)
  • version_number (INT)
  • version_data (JSON/BLOB)
  • change_description (TEXT)
  • created_by (user_id)
  • created_at (TIMESTAMP)

Plugin

  • plugin_id (UUID)
  • creator_id (user_id)
  • plugin_name (VARCHAR)
  • plugin_code (TEXT)
  • version (VARCHAR)
  • is_verified (BOOLEAN)
  • download_count (INT)
  • created_at (TIMESTAMP)

API

1. Create Project

POST /api/v1/projects
Request:
{
  "project_name": "My Game",
  "description": "A fun game"
}

Response:
{
  "project_id": "uuid",
  "project_name": "My Game",
  "version": 1,
  "created_at": "2025-11-16T10:00:00Z"
}

2. Open Team Create Session

POST /api/v1/projects/{project_id}/team-create
Request:
{
  "max_collaborators": 10
}

Response:
{
  "session_id": "uuid",
  "project_id": "uuid",
  "host_user_id": "uuid",
  "join_token": "encrypted_token",
  "websocket_url": "wss://studio.roblox.com/ws/{session_id}"
}

3. Join Team Create Session

POST /api/v1/team-create/{session_id}/join
Request:
{
  "join_token": "encrypted_token",
  "user_id": "uuid"
}

Response:
{
  "session_id": "uuid",
  "current_collaborators": [
    {"user_id": "uuid", "username": "creator1"},
    {"user_id": "uuid", "username": "creator2"}
  ],
  "project_state": {...}
}

4. Send Collaboration Event

POST /api/v1/team-create/{session_id}/events
Request:
{
  "event_type": "update",
  "target_object": "Workspace.Part1",
  "event_data": {
    "position": {"x": 10, "y": 5, "z": 0},
    "color": "Bright blue"
  }
}

Response:
{
  "event_id": "uuid",
  "sequence_number": 123,
  "timestamp": "2025-11-16T10:01:00Z"
}

5. Sync Project

POST /api/v1/projects/{project_id}/sync
Request:
{
  "project_data": {...},
  "version": 5
}

Response:
{
  "project_id": "uuid",
  "new_version": 6,
  "conflicts": [],
  "synced_at": "2025-11-16T10:02:00Z"
}

6. Upload Asset

POST /api/v1/assets
Request:
{
  "asset_type": "model",
  "asset_name": "MyModel",
  "asset_data": "base64_encoded_data"
}

Response:
{
  "asset_id": "uuid",
  "asset_url": "https://cdn.roblox.com/assets/...",
  "file_size": 1024000,
  "status": "uploaded"
}

7. Get Project History

GET /api/v1/projects/{project_id}/versions?limit=20&offset=0
Response:
{
  "versions": [
    {
      "version_id": "uuid",
      "version_number": 6,
      "change_description": "Added new level",
      "created_by": "uuid",
      "created_at": "2025-11-16T10:00:00Z"
    }
  ],
  "total": 50,
  "limit": 20,
  "offset": 0
}

8. Publish Project

POST /api/v1/projects/{project_id}/publish
Request:
{
  "experience_name": "My Published Game",
  "description": "...",
  "is_public": true
}

Response:
{
  "project_id": "uuid",
  "experience_id": "uuid",
  "published_url": "https://www.roblox.com/games/...",
  "status": "published"
}

Data Flow

Team Create Session Flow

  1. Host Opens Team Create:
    • Creator opens Team Create for project
    • Studio Client sends request to API Gateway
    • API Gateway routes to Team Create Service
  2. Session Creation:
    • Team Create Service:
      • Creates session record
      • Generates join token
      • Establishes WebSocket connection
      • Loads current project state
      • Returns session info to host
  3. Collaborator Joins:
    • Collaborator uses join token
    • Team Create Service:
      • Validates token
      • Adds collaborator to session
      • Sends current project state
      • Establishes WebSocket connection
      • Notifies other collaborators
  4. Real-Time Collaboration:
    • Creator makes change (move object, edit property)
    • Studio Client sends event to Team Create Service
    • Team Create Service:
      • Validates event
      • Applies to project state
      • Broadcasts to all collaborators via WebSocket
      • Stores event in collaboration log
  5. State Synchronization:
    • All collaborators receive update
    • Studio Client applies change locally
    • UI updates in real-time
    • Conflict resolution if needed

Project Sync Flow

  1. User Saves Project:
    • User clicks Save in Studio
    • Studio Client prepares project data
    • Sends sync request to Project Service
  2. Conflict Detection:
    • Project Service:
      • Gets current server version
      • Compares with client version
      • Detects conflicts if any
  3. Conflict Resolution:
    • If conflicts detected:
      • Project Service returns conflict list
      • Studio Client shows conflict resolution UI
      • User resolves conflicts
      • Resends sync request
  4. Sync Completion:
    • Project Service:
      • Stores new version
      • Updates project metadata
      • Creates version history entry
      • Returns success

Asset Upload Flow

  1. User Uploads Asset:
    • User drags file into Studio
    • Studio Client reads file
    • Sends upload request to Asset Service
  2. Asset Processing:
    • Asset Service:
      • Validates file type and size
      • Generates asset ID
      • Uploads to object storage (S3)
      • Processes asset (validation, optimization)
  3. Asset Registration:
    • Asset Service:
      • Creates asset metadata record
      • Generates CDN URL
      • Returns asset info to client
  4. Asset Available:
    • Asset appears in Studio library
    • Available for use in projects
    • Can be shared with team

Database Design

Schema Design

Projects Table:

CREATE TABLE projects (
    project_id UUID PRIMARY KEY,
    creator_id UUID NOT NULL,
    project_name VARCHAR(200) NOT NULL,
    description TEXT,
    project_data JSONB NOT NULL,
    version INT DEFAULT 1,
    is_published BOOLEAN DEFAULT FALSE,
    published_experience_id UUID,
    created_at TIMESTAMP DEFAULT NOW(),
    updated_at TIMESTAMP DEFAULT NOW(),
    last_synced_at TIMESTAMP,
    INDEX idx_creator_id (creator_id),
    INDEX idx_is_published (is_published),
    INDEX idx_updated_at (updated_at DESC)
);

Team Create Sessions Table:

CREATE TABLE team_create_sessions (
    session_id UUID PRIMARY KEY,
    project_id UUID NOT NULL,
    host_user_id UUID NOT NULL,
    session_status VARCHAR(20) DEFAULT 'active',
    max_collaborators INT DEFAULT 10,
    current_collaborators JSONB NOT NULL,
    created_at TIMESTAMP DEFAULT NOW(),
    updated_at TIMESTAMP DEFAULT NOW(),
    INDEX idx_project_id (project_id),
    INDEX idx_host_user_id (host_user_id),
    INDEX idx_session_status (session_status)
);

Collaboration Events Table (Sharded by session_id):

CREATE TABLE collaboration_events_0 (
    event_id UUID PRIMARY KEY,
    session_id UUID NOT NULL,
    user_id UUID NOT NULL,
    event_type VARCHAR(50) NOT NULL,
    target_object VARCHAR(500) NOT NULL,
    event_data JSONB NOT NULL,
    timestamp TIMESTAMP DEFAULT NOW(),
    sequence_number INT NOT NULL,
    INDEX idx_session_id (session_id),
    INDEX idx_session_sequence (session_id, sequence_number),
    INDEX idx_timestamp (timestamp DESC)
);
-- Similar tables: collaboration_events_1, ..., collaboration_events_N

Assets Table:

CREATE TABLE assets (
    asset_id UUID PRIMARY KEY,
    creator_id UUID NOT NULL,
    asset_type VARCHAR(50) NOT NULL,
    asset_name VARCHAR(200) NOT NULL,
    asset_url VARCHAR(1000) NOT NULL,
    file_size BIGINT NOT NULL,
    tags JSONB,
    is_public BOOLEAN DEFAULT FALSE,
    created_at TIMESTAMP DEFAULT NOW(),
    INDEX idx_creator_id (creator_id),
    INDEX idx_asset_type (asset_type),
    INDEX idx_tags (tags),
    FULLTEXT INDEX idx_asset_name (asset_name)
);

Project Versions Table (Sharded by project_id):

CREATE TABLE project_versions_0 (
    version_id UUID PRIMARY KEY,
    project_id UUID NOT NULL,
    version_number INT NOT NULL,
    version_data JSONB NOT NULL,
    change_description TEXT,
    created_by UUID NOT NULL,
    created_at TIMESTAMP DEFAULT NOW(),
    INDEX idx_project_id (project_id),
    INDEX idx_project_version (project_id, version_number),
    INDEX idx_created_at (created_at DESC)
);
-- Similar tables: project_versions_1, ..., project_versions_N

Database Sharding Strategy

Collaboration Events Table Sharding:

  • Shard by session_id using consistent hashing
  • 1000 shards: shard_id = hash(session_id) % 1000
  • All events for a session in same shard
  • Enables efficient event replay

Project Versions Table Sharding:

  • Shard by project_id using consistent hashing
  • 1000 shards: shard_id = hash(project_id) % 1000
  • All versions for a project in same shard
  • Enables efficient version queries

Shard Key Selection:

  • Ensures related data is co-located
  • Enables efficient queries
  • Prevents cross-shard queries for single entity

Replication:

  • Each shard replicated 3x for high availability
  • Master-replica setup for read scaling
  • Writes go to master, reads can go to replicas

High-Level Design

┌─────────────┐
│ Studio      │
│ Client      │
│ (Desktop)   │
└──────┬──────┘
       │
       │ HTTP/WebSocket
       │
┌──────▼──────────────────────────────────────────────┐
│        API Gateway / Load Balancer                   │
│        - Rate Limiting                               │
│        - Request Routing                             │
└──────┬──────────────────────────────────────────────┘
       │
       ├──────────────┬──────────────┬──────────────┬──────────────┐
       │              │              │              │              │
┌──────▼──────┐ ┌─────▼──────┐ ┌─────▼──────┐ ┌─────▼──────┐ ┌─────▼──────┐
│ Project     │ │ Team Create │ │ Asset      │ │ Plugin     │ │ Publishing │
│ Service     │ │ Service     │ │ Service    │ │ Service    │ │ Service    │
└──────┬──────┘ └─────┬──────┘ └─────┬──────┘ └─────┬──────┘ └─────┬──────┘
       │              │              │              │              │
       │              │              │              │              │
┌──────▼──────────────▼──────────────▼──────────────▼──────────────▼──────┐
│              Message Queue (Kafka)                                        │
│              - Collaboration events                                         │
│              - Project sync events                                          │
│              - Asset processing jobs                                        │
└──────┬───────────────────────────────────────────────────────────────────┘
       │
       │
┌──────▼───────────────────────────────────────────────────────────────────┐
│         WebSocket Service                                                 │
│         - Real-time collaboration updates                                 │
│         - State synchronization                                           │
│         - Presence management                                              │
└──────┬───────────────────────────────────────────────────────────────────┘
       │
       │
┌──────▼───────────────────────────────────────────────────────────────────┐
│         Database Cluster (Sharded)                                         │
│  ┌──────────┐  ┌──────────┐  ┌──────────┐                              │
│  │ Projects │  │ Team     │  │ Assets   │                              │
│  │ DB       │  │ Create   │  │ DB       │                              │
│  │          │  │ Sessions │  │          │                              │
│  └──────────┘  └──────────┘  └──────────┘                              │
│                                                                           │
│  ┌──────────┐  ┌──────────┐                                              │
│  │ Collaboration│ │ Project │                                              │
│  │ Events        │ │ Versions│                                              │
│  │ (Sharded)     │ │ (Sharded)│                                             │
│  └──────────┘  └──────────┘                                              │
└───────────────────────────────────────────────────────────────────────────┘

┌───────────────────────────────────────────────────────────────────────────┐
│              Object Storage (S3)                                           │
│              - Project backups                                             │
│              - Asset files                                                 │
│              - Version snapshots                                           │
└───────────────────────────────────────────────────────────────────────────┘

┌───────────────────────────────────────────────────────────────────────────┐
│              CDN (CloudFront)                                              │
│              - Asset delivery                                              │
│              - Fast downloads                                              │
└───────────────────────────────────────────────────────────────────────────┘

┌───────────────────────────────────────────────────────────────────────────┐
│         Conflict Resolution Service                                        │
│         - Detect conflicts                                                 │
│         - Merge strategies                                                 │
│         - Conflict resolution UI                                          │
└───────────────────────────────────────────────────────────────────────────┘

Deep Dive

Component Design

1. Team Create Service

Responsibilities:

  • Manage Team Create sessions
  • Handle real-time collaboration
  • Synchronize state across collaborators
  • Resolve conflicts

Key Design Decisions:

  • Operational Transformation (OT): Use OT for conflict resolution
  • Event Sourcing: Store all collaboration events
  • WebSocket: Real-time bidirectional communication
  • State Management: Centralized state on server

Implementation:

class TeamCreateService:
    def __init__(self):
        self.sessions = {}  # session_id -> Session
        self.websocket_manager = WebSocketManager()
        self.ot_engine = OperationalTransformationEngine()
    
    def create_session(self, project_id, host_user_id, max_collaborators=10):
        """Create Team Create session"""
        session_id = generate_uuid()
        
        # Load project state
        project = self.get_project(project_id)
        
        # Create session
        session = TeamCreateSession(
            session_id=session_id,
            project_id=project_id,
            host_user_id=host_user_id,
            max_collaborators=max_collaborators,
            project_state=project.project_data,
            collaborators=[host_user_id]
        )
        
        self.sessions[session_id] = session
        
        # Establish WebSocket for host
        self.websocket_manager.connect(session_id, host_user_id)
        
        return session
    
    def join_session(self, session_id, user_id, join_token):
        """Join Team Create session"""
        session = self.sessions.get(session_id)
        if not session:
            raise SessionNotFoundError("Session not found")
        
        # Validate token
        if not self.validate_token(session_id, join_token):
            raise InvalidTokenError("Invalid join token")
        
        # Check capacity
        if len(session.collaborators) >= session.max_collaborators:
            raise SessionFullError("Session is full")
        
        # Add collaborator
        session.collaborators.append(user_id)
        
        # Establish WebSocket
        self.websocket_manager.connect(session_id, user_id)
        
        # Send current state to new collaborator
        self.websocket_manager.send(user_id, {
            'type': 'session_joined',
            'project_state': session.project_state,
            'collaborators': session.collaborators
        })
        
        # Notify other collaborators
        self.broadcast_to_others(session_id, user_id, {
            'type': 'collaborator_joined',
            'user_id': user_id
        })
        
        return session
    
    def handle_collaboration_event(self, session_id, user_id, event):
        """Handle collaboration event"""
        session = self.sessions.get(session_id)
        if not session:
            raise SessionNotFoundError("Session not found")
        
        if user_id not in session.collaborators:
            raise UnauthorizedError("Not a collaborator")
        
        # Transform event using OT
        transformed_event = self.ot_engine.transform(
            event,
            session.get_pending_events(user_id)
        )
        
        # Apply to state
        session.apply_event(transformed_event)
        
        # Store event
        self.store_event(session_id, user_id, transformed_event)
        
        # Broadcast to all collaborators
        self.broadcast_to_all(session_id, {
            'type': 'collaboration_event',
            'event': transformed_event,
            'user_id': user_id
        })
        
        return transformed_event

2. Operational Transformation Engine

Responsibilities:

  • Transform operations to resolve conflicts
  • Maintain operation order
  • Handle concurrent edits

Key Design Decisions:

  • OT Algorithm: Use standard OT algorithms
  • Operation Types: Insert, Update, Delete, Move
  • Transformation Rules: Define transformation for each operation pair

Implementation:

class OperationalTransformationEngine:
    def transform(self, operation, concurrent_operations):
        """Transform operation against concurrent operations"""
        transformed_op = operation
        
        for concurrent_op in concurrent_operations:
            transformed_op = self.transform_pair(transformed_op, concurrent_op)
        
        return transformed_op
    
    def transform_pair(self, op1, op2):
        """Transform op1 against op2"""
        # Handle different operation types
        if op1.type == 'insert' and op2.type == 'insert':
            return self.transform_insert_insert(op1, op2)
        elif op1.type == 'update' and op2.type == 'update':
            return self.transform_update_update(op1, op2)
        elif op1.type == 'delete' and op2.type == 'delete':
            return self.transform_delete_delete(op1, op2)
        # ... other combinations
        
        return op1
    
    def transform_insert_insert(self, op1, op2):
        """Transform insert against insert"""
        # If op1 inserts before op2, no change needed
        if op1.position < op2.position:
            return op1
        # If op1 inserts after op2, adjust position
        elif op1.position > op2.position:
            op1.position += op2.length
            return op1
        # Same position - use user_id for tie-breaking
        else:
            if op1.user_id < op2.user_id:
                return op1
            else:
                op1.position += op2.length
                return op1

3. Project Sync Service

Responsibilities:

  • Sync projects between client and server
  • Detect conflicts
  • Resolve conflicts
  • Manage version history

Key Design Decisions:

  • Version Control: Git-like versioning
  • Conflict Detection: Compare versions
  • Merge Strategies: Automatic and manual merge
  • Delta Sync: Send only changes

Implementation:

class ProjectSyncService:
    def __init__(self):
        self.version_manager = VersionManager()
        self.conflict_resolver = ConflictResolver()
    
    def sync_project(self, project_id, client_data, client_version):
        """Sync project from client"""
        # Get server version
        server_version = self.version_manager.get_latest_version(project_id)
        
        if client_version == server_version.version_number:
            # No conflicts, simple update
            new_version = self.version_manager.create_version(
                project_id, client_data, client_version + 1
            )
            return {
                'status': 'synced',
                'new_version': new_version.version_number,
                'conflicts': []
            }
        else:
            # Conflicts detected
            conflicts = self.detect_conflicts(
                server_version.version_data,
                client_data
            )
            
            if conflicts:
                return {
                    'status': 'conflicts',
                    'conflicts': conflicts,
                    'server_version': server_version.version_data
                }
            else:
                # Auto-merge possible
                merged_data = self.auto_merge(
                    server_version.version_data,
                    client_data
                )
                new_version = self.version_manager.create_version(
                    project_id, merged_data, server_version.version_number + 1
                )
                return {
                    'status': 'synced',
                    'new_version': new_version.version_number,
                    'conflicts': []
                }
    
    def detect_conflicts(self, server_data, client_data):
        """Detect conflicts between versions"""
        conflicts = []
        
        # Compare object hierarchies
        server_objects = self.extract_objects(server_data)
        client_objects = self.extract_objects(client_data)
        
        # Find modified objects
        for obj_id in set(server_objects.keys()) & set(client_objects.keys()):
            server_obj = server_objects[obj_id]
            client_obj = client_objects[obj_id]
            
            if server_obj != client_obj:
                conflicts.append({
                    'object_id': obj_id,
                    'server_value': server_obj,
                    'client_value': client_obj
                })
        
        return conflicts

4. Asset Service

Responsibilities:

  • Upload and store assets
  • Process and validate assets
  • Serve assets via CDN
  • Manage asset library

Key Design Decisions:

  • Object Storage: Use S3 for storage
  • CDN Distribution: Serve via CDN
  • Asset Processing: Validate and optimize
  • Versioning: Version assets

Implementation:

class AssetService:
    def __init__(self):
        self.s3_client = S3Client()
        self.cdn_client = CDNClient()
        self.asset_processor = AssetProcessor()
    
    def upload_asset(self, creator_id, asset_type, asset_name, asset_data):
        """Upload asset"""
        # Validate asset
        validation_result = self.validate_asset(asset_type, asset_data)
        if not validation_result.is_valid:
            raise InvalidAssetError(validation_result.error)
        
        # Generate asset ID
        asset_id = generate_asset_id()
        
        # Process asset
        processed_data = self.asset_processor.process(
            asset_type, asset_data
        )
        
        # Upload to S3
        s3_key = f"assets/{asset_type}/{asset_id}"
        self.s3_client.upload(s3_key, processed_data)
        
        # Invalidate CDN cache
        cdn_url = self.cdn_client.get_url(s3_key)
        self.cdn_client.invalidate(cdn_url)
        
        # Create asset record
        asset = Asset(
            asset_id=asset_id,
            creator_id=creator_id,
            asset_type=asset_type,
            asset_name=asset_name,
            asset_url=cdn_url,
            file_size=len(processed_data)
        )
        asset.save()
        
        return asset

Detailed Design

Real-Time Collaboration Architecture

Challenge: Synchronize edits across multiple collaborators in real-time

Solution:

  • Operational Transformation: Transform operations to resolve conflicts
  • Event Sourcing: Store all events for replay
  • WebSocket: Real-time bidirectional communication
  • State Management: Centralized state on server

Implementation:

class CollaborationManager:
    def __init__(self):
        self.sessions = {}
        self.ot_engine = OperationalTransformationEngine()
        self.event_store = EventStore()
    
    def apply_event(self, session_id, event):
        """Apply event to session"""
        session = self.sessions[session_id]
        
        # Get concurrent events
        concurrent_events = session.get_concurrent_events(event.timestamp)
        
        # Transform event
        transformed_event = self.ot_engine.transform(event, concurrent_events)
        
        # Apply to state
        session.apply_event(transformed_event)
        
        # Store event
        self.event_store.append(session_id, transformed_event)
        
        # Broadcast to collaborators
        self.broadcast_event(session_id, transformed_event)

Conflict Resolution Strategies

Challenge: Resolve conflicts when multiple users edit same object

Solution:

  • Last Write Wins: Simple but may lose data
  • Manual Resolution: User chooses which version
  • Automatic Merge: Merge non-conflicting changes
  • Operational Transformation: Transform operations

Implementation:

class ConflictResolver:
    def resolve_conflicts(self, conflicts, strategy='auto'):
        """Resolve conflicts"""
        if strategy == 'last_write_wins':
            return self.last_write_wins(conflicts)
        elif strategy == 'manual':
            return self.manual_resolution(conflicts)
        elif strategy == 'auto':
            return self.auto_merge(conflicts)
    
    def auto_merge(self, conflicts):
        """Automatically merge conflicts"""
        merged = {}
        for conflict in conflicts:
            obj_id = conflict['object_id']
            server_obj = conflict['server_value']
            client_obj = conflict['client_value']
            
            # Merge non-conflicting properties
            merged_obj = {}
            for key in set(server_obj.keys()) | set(client_obj.keys()):
                if key in server_obj and key in client_obj:
                    if server_obj[key] == client_obj[key]:
                        merged_obj[key] = server_obj[key]
                    else:
                        # Conflict - use server value
                        merged_obj[key] = server_obj[key]
                elif key in server_obj:
                    merged_obj[key] = server_obj[key]
                else:
                    merged_obj[key] = client_obj[key]
            
            merged[obj_id] = merged_obj
        
        return merged

Scalability Considerations

Horizontal Scaling

Team Create Service:

  • Stateless service, horizontally scalable
  • Session state in Redis or database
  • WebSocket connections distributed
  • Load balancer for WebSocket connections

Project Service:

  • Stateless service, horizontally scalable
  • Projects stored in database
  • CDN for asset delivery
  • Horizontal scaling for processing

Caching Strategy

Redis Cache:

  • Active Sessions: Cache active Team Create sessions
  • Project State: Cache recent project states
  • Asset Metadata: Cache asset information
  • TTL: 1 hour for sessions, 30 min for projects

Security Considerations

Access Control

  • Project Ownership: Verify creator owns project
  • Team Create Permissions: Verify user can join session
  • Asset Access: Control asset visibility
  • Plugin Security: Sandbox plugin execution

Data Protection

  • Encryption: Encrypt sensitive project data
  • Access Logging: Log all access attempts
  • Rate Limiting: Limit API calls per user
  • Input Validation: Validate all inputs

Monitoring & Observability

Key Metrics

Platform Metrics:

  • Active Team Create sessions
  • Collaboration events per second
  • Project syncs per day
  • Asset uploads per day
  • Average session duration

Performance Metrics:

  • Collaboration latency (p50, p95, p99)
  • Project sync latency
  • Asset upload latency
  • WebSocket connection count

Business Metrics:

  • Active creators
  • Projects created
  • Assets uploaded
  • Team Create usage

Trade-offs and Optimizations

Trade-offs

1. Consistency: Strong vs Eventual

  • Strong: Better collaboration, higher latency
  • Eventual: Lower latency, eventual consistency
  • Decision: Strong for collaboration, eventual for sync

2. Conflict Resolution: Automatic vs Manual

  • Automatic: Faster, may lose data
  • Manual: Slower, preserves data
  • Decision: Automatic for simple conflicts, manual for complex

3. State Storage: Memory vs Database

  • Memory: Faster, limited capacity
  • Database: Slower, unlimited capacity
  • Decision: Hybrid - memory for active, database for persistence

Optimizations

1. Delta Compression

  • Send only changes
  • Reduce bandwidth
  • Improve performance

2. Batching

  • Batch multiple events
  • Reduce overhead
  • Improve throughput

3. Lazy Loading

  • Load assets on demand
  • Reduce initial load time
  • Improve startup performance

What Interviewers Look For

Real-Time Collaboration Skills

  1. Operational Transformation
    • Conflict resolution
    • Concurrent editing
    • State synchronization
    • Red Flags: No conflict resolution, data loss, overwrites
  2. Event Sourcing
    • Collaboration history
    • Replay capability
    • Red Flags: No history, no replay, data loss
  3. WebSocket Architecture
    • Real-time updates
    • Bidirectional communication
    • Red Flags: Polling, high latency, no real-time

IDE/Developer Tools Skills

  1. Modular Architecture
    • Plugin system
    • Extensibility
    • Red Flags: Monolithic, no plugins, not extensible
  2. Version Control
    • Project history
    • Branching/merging
    • Red Flags: No version control, no history, data loss
  3. Offline Support
    • Work offline
    • Sync when online
    • Red Flags: No offline, network required, poor UX

Distributed Systems Skills

  1. State Management
    • Project state sync
    • Conflict resolution
    • Red Flags: No sync, conflicts, data loss
  2. Scalability Design
    • Horizontal scaling
    • Database sharding
    • Red Flags: Vertical scaling, no sharding, bottlenecks
  3. Asset Management
    • Efficient storage
    • CDN distribution
    • Red Flags: Inefficient storage, slow delivery, no CDN

Problem-Solving Approach

  1. Conflict Resolution
    • Automatic strategies
    • Manual fallback
    • Red Flags: No resolution, data loss, overwrites
  2. Edge Cases
    • Concurrent edits
    • Network failures
    • Plugin failures
    • Red Flags: Ignoring edge cases, no handling
  3. Trade-off Analysis
    • Consistency vs latency
    • Strong vs eventual
    • Red Flags: No trade-offs, dogmatic choices

System Design Skills

  1. Component Design
    • Collaboration service
    • Asset service
    • Plugin service
    • Red Flags: Monolithic, unclear boundaries
  2. Security Design
    • Plugin sandbox
    • Access control
    • Red Flags: No sandbox, insecure, vulnerabilities
  3. Performance Optimization
    • Delta compression
    • Lazy loading
    • Red Flags: No optimization, slow, poor UX

Communication Skills

  1. Collaboration Algorithm Explanation
    • Can explain OT
    • Understands conflict resolution
    • Red Flags: No understanding, vague
  2. Architecture Justification
    • Explains design decisions
    • Discusses alternatives
    • Red Flags: No justification, no alternatives

Meta-Specific Focus

  1. Real-Time Collaboration Expertise
    • OT knowledge
    • Conflict resolution
    • Key: Show collaboration expertise
  2. Developer Tools Expertise
    • IDE architecture
    • Plugin systems
    • Key: Demonstrate tools expertise

Summary

Designing Roblox Studio requires careful consideration of:

  1. Real-Time Collaboration: Operational Transformation for conflict resolution
  2. IDE Architecture: Modular architecture for extensibility
  3. Project Management: Version control and sync
  4. Asset Management: Efficient storage and delivery
  5. Plugin System: Secure plugin execution
  6. Offline Support: Work offline, sync when online
  7. Scalability: Handle 100K+ concurrent Team Create sessions
  8. Performance: Sub-100ms collaboration latency
  9. Conflict Resolution: Automatic and manual strategies
  10. Cross-Platform: Support Windows and Mac

Key architectural decisions:

  • Operational Transformation for real-time collaboration
  • WebSocket for bidirectional communication
  • Event Sourcing for collaboration history
  • Sharded Database for scalability
  • CDN Distribution for asset delivery
  • Version Control for project history
  • Plugin Sandbox for security
  • Horizontal Scaling for all services

The system handles 100,000 concurrent Team Create sessions, processes 10 million collaboration events per second, manages petabytes of project data, and provides sub-100ms collaboration latency while ensuring data consistency and supporting offline editing.