There isn’t a universally perfect setup for web applications, as requirements and preferences vary greatly depending on factors such as project size, complexity, team expertise, and specific goals, there are certainly best practices and common patterns that can guide you towards a robust setup. Here’s a generalised outline of components and practices often considered essential for a solid web application setup and a guide to team knowledges which you need to have:

1. Frontend Framework/Library: Choose a frontend framework or library based on your project’s requirements and team expertise. Popular choices include React.js, Vue.js, Angular, and Svelte. These frameworks/libraries help in building interactive user interfaces and managing application state efficiently.
2. Backend Framework: Select a backend framework that aligns with your project’s requirements and the programming language you’re comfortable with. Popular choices include Express.js (Node.js), Django (Python), Ruby on Rails (Ruby), Laravel (PHP), and ASP.NET Core (C#). These frameworks provide tools and patterns for building scalable and maintainable backend services.
3. Database: Choose a suitable database management system (DBMS) based on factors like data structure, scalability, and performance requirements. Common choices include relational databases like PostgreSQL, MySQL, SQL Server, and SQLite, as well as NoSQL databases like MongoDB, Cassandra, and Redis.
4. RESTful API or GraphQL: Design and implement an API layer to expose backend functionality to frontend clients. Decide whether to use RESTful APIs or GraphQL based on factors like data complexity, client requirements, and performance considerations.
5. Authentication and Authorization: Implement secure authentication and authorization mechanisms to protect your application’s resources and data. Use industry-standard protocols like OAuth 2.0 or OpenID Connect for authentication and role-based access control (RBAC) or permissions-based authorization for controlling access to resources.
6. Security: Pay close attention to security best practices to protect your application from common threats like cross-site scripting (XSS), SQL injection, cross-site request forgery (CSRF), and insecure direct object references (IDOR). Implement features like input validation, parameterized queries, HTTPS, and content security policy (CSP) headers to enhance security.
7. Frontend Build Tools: Use build tools like Webpack, Parcel, or Rollup.js to bundle and optimize frontend assets such as JavaScript, CSS, and images. Utilize features like code splitting, tree shaking, and minification to improve performance and reduce load times.
8. Version Control: Utilize a version control system like Git to track changes to your application’s source code and collaborate with team members effectively. Host your repository on platforms like GitHub, GitLab, or Bitbucket for centralized collaboration and code review workflows.
9. Continuous Integration/Continuous Deployment (CI/CD): Implement CI/CD pipelines to automate testing, code quality checks, and deployment processes. Utilize tools like Jenkins, Travis CI, CircleCI, or GitHub Actions to automate build, test, and deployment workflows, ensuring consistent and reliable releases.
10. Monitoring and Logging: Set up monitoring and logging solutions to track application performance, detect errors, and troubleshoot issues in real-time. Use tools like Prometheus, Grafana, ELK stack (Elasticsearch, Logstash, Kibana), or Sentry for monitoring, logging, and error tracking.
11. Scalability and Performance Optimization: Design your application with scalability in mind and optimize performance by employing techniques like caching, database indexing, asynchronous processing, and horizontal scaling. Monitor resource usage and performance metrics to identify bottlenecks and optimize critical paths.
12. Documentation and Testing: Document your application’s architecture, APIs, and deployment processes to facilitate onboarding and maintenance. Write comprehensive unit tests, integration tests, and end-to-end tests to ensure code quality, reliability, and maintainability.
13. DevOps Practices: Embrace DevOps practices like infrastructure as code (IaC), configuration management, and automated provisioning to streamline deployment processes and improve collaboration between development and operations teams.
14. User Experience (UX) and Accessibility: Prioritize user experience and accessibility by following UX design principles and implementing accessible design patterns. Conduct usability testing and ensure that your application is accessible to users with disabilities.
15. Community and Support: Engage with the developer community, participate in forums, attend conferences, and leverage online resources like documentation, tutorials, and forums to stay updated on best practices, emerging technologies, and troubleshooting tips.

Remember that the ideal setup for a web application may vary based on your project’s unique requirements, constraints, and goals. Continuously evaluate and iterate on your application setup to adapt to changing requirements and incorporate new technologies and best practices.