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💡 Pro Tip: Port 4201 is commonly used as a backup when port 4200 is already in use by another Angular application or development server.

Quick Commands for Angular Port 4201

Start Angular on port 4201:
ng serve --port 4201
npm start -- --port 4201

Find what's using port 4201:
lsof -i :4201 (Mac/Linux)
netstat -ano | findstr :4201 (Windows)

Kill process on port 4201:
kill -9 $(lsof -t -i:4201) (Mac/Linux)
for /f "tokens=5" %a in ('netstat -aon ^| findstr :4201') do taskkill /PID %a /F (Windows)

Check Angular version:
ng version
npm list @angular/core

About Port 4201

Port 4201 is commonly used for:

Angular backup - When port 4200 is busy
Multiple Angular apps - Running simultaneously
Development testing - Different versions
Ionic backup - Mobile app development
Angular workspaces - Multiple projects

Common Use Cases

Running multiple Angular applications during development
Testing different versions of the same Angular app
Micro-frontends architecture with multiple Angular apps
Angular workspace with multiple projects
Development and testing environments running in parallel

🔄 Angular Multi-Port Development

Managing multiple Angular applications and development scenarios on different ports

Multiple Application Setup

ng serve --port 4200 - Main application
ng serve --port 4201 - Secondary application
ng serve --port 4202 - Third application
Configure different environments
Set up proxy configurations

Development Workflows

Feature branch development
Parallel development testing
Version comparison testing
Micro-frontend development
Team collaboration scenarios

Port Management

Automatic port detection
Manual port assignment
Port conflict resolution
Port range configuration
Environment-specific ports

Testing & Quality

Cross-application testing
Integration testing setup
Performance comparison
Browser compatibility testing
Load testing scenarios

📁 Angular Workspace Management

Managing Angular workspaces with multiple projects and applications

Workspace Configuration

ng new my-workspace --create-application=false
ng generate application app1 - Create app
ng generate library my-lib - Create library
Configure angular.json for multiple apps
Set up shared dependencies

Multi-Application Development

ng serve app1 --port 4200
ng serve app2 --port 4201
Shared component libraries
Common styling and themes
Unified build processes

Library Development

ng build my-lib - Build library
ng test my-lib - Test library
Library versioning strategies
Publishing to npm registry
Library documentation

Deployment Strategies

Individual app deployment
Monorepo deployment
Shared asset management
Environment configuration
CI/CD pipeline setup

🎯 Angular Development Scenarios

Common development scenarios and solutions for port 4201

Feature Development

Isolated feature development:

Create feature branch for new functionality
Run development server on port 4201
Test feature independently
Compare with main application
Integration testing before merge

Version Testing

Testing different versions:

Run current version on port 4200
Run new version on port 4201
Side-by-side comparison
Performance benchmarking
User acceptance testing

Team Collaboration

Multi-developer scenarios:

Different developers on different ports
Code review and testing
Shared development environment
Conflict resolution strategies
Team development workflows

Micro-Frontend Development

Micro-frontend architecture:

Independent micro-applications
Shared component libraries
Module federation setup
Cross-application communication
Unified deployment strategy

⚙️ Angular Configuration & Optimization

Advanced configuration and optimization for Angular applications on port 4201

angular.json Configuration

Configure multiple serve targets
Set default ports for applications
Configure build optimizations
Set up proxy configurations
Environment-specific settings

Performance Tuning

Optimize change detection
Configure bundle splitting
Set up lazy loading
Optimize template compilation
Configure caching strategies

Development Tools

Configure source maps
Set up debugging tools
Configure hot reload
Set up testing frameworks
Configure linting rules

Environment Management

Environment-specific configurations
API endpoint management
Feature flag configuration
Build optimization settings
Deployment configurations

📋 Port 4201 Development Summary

Port 4201 serves as a strategic backup and alternative development port for Angular applications, enabling developers to run multiple Angular applications simultaneously or handle port conflicts efficiently. It's particularly valuable for complex development scenarios involving feature branches, version testing, team collaboration, and micro-frontend architectures.

Understanding how to effectively manage multiple Angular applications across different ports, configure workspaces, and implement advanced development workflows is essential for modern Angular development teams. Port 4201 provides the flexibility needed for sophisticated development scenarios while maintaining the same powerful development features as the primary port 4200.

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