Web development apps, also known as web development tools or software, are applications and platforms designed to assist web developers in creating, testing, and maintaining websites and web applications. These tools help streamline the development process, improve productivity, and provide features for coding, debugging, designing, and more. Here are some essential web development apps and categories:

1. Code Editors and Integrated Development Environments (IDEs):
   
   1. Visual Studio Code (VS Code): A popular, free, and open-source code editor known for its extensive extensions and support for various programming languages.
   2. Sublime Text: A lightweight, highly customizable text editor with a strong developer community and package support.
   3. Atom: An open-source text editor developed by GitHub, customizable through packages and themes.
   4. WebStorm: A professional IDE for web development with JavaScript, HTML, and CSS support.
2. Version Control Systems:
   
   1. Git: A distributed version control system used for tracking changes in code and collaborating with development teams.
   2. GitHub: A web-based platform that provides hosting for Git repositories and features for code collaboration.
3. Web Browsers with Developer Tools:
   
   1. Google Chrome: Offers developer tools for inspecting and debugging web pages.
   2. Firefox: Includes a set of developer tools for web development and debugging.
   3. Microsoft Edge: Provides developer tools similar to Chrome for web development tasks.
4. Graphics and Design Tools:
   
   1. Adobe XD: A design and prototyping tool for creating user interfaces and website mockups.
   2. Sketch: A macOS design tool for creating vector graphics, user interfaces, and website designs.
   3. Figma: A collaborative design tool accessible in the browser for UI/UX design and prototyping.
5. Local Development Environments:
   
   1. XAMPP: A local server environment for PHP development with Apache, MySQL, and PHP.
   2. MAMP: A macOS-based local server environment for web development with Apache, MySQL, and PHP.
6. Database Management Tools:
   
   1. phpMyAdmin: A web-based tool for managing MySQL databases.
   2. Adminer: A lightweight and easy-to-use database management tool for various database systems.
   3. Sequel Pro: A macOS application for managing MySQL databases.
7. API Development and Testing:
   
   1. Postman: A tool for testing and documenting APIs by sending HTTP requests and inspecting responses.
   2. Swagger/OpenAPI: A framework for designing, building, and documenting RESTful APIs.
8. Web Performance Testing:
   
   1. Lighthouse: A tool integrated into Chrome’s developer tools for auditing web page performance and accessibility.
   2. WebPageTest: A website testing tool that provides insights into website speed and performance.
9. Code Collaboration and Communication:
   
   1. Slack: A messaging platform for team communication and collaboration.
   2. Trello: A project management tool for organizing tasks and tracking progress.
10. FTP Clients:
    
    1. FileZilla: A popular, free FTP client for transferring files to and from a web server.
    2. Cyberduck: An open-source FTP and SFTP client with support for various protocols.
11. Task Runners and Build Tools:
    
    1. Grunt: A JavaScript task runner for automating repetitive tasks in the development workflow.
    2. Gulp: A build system and task runner that simplifies building and optimizing web projects.
12. Content Management Systems (CMS):
    
    1. WordPress: A popular CMS that simplifies web content management and is extendable with plugins and themes.
    2. Drupal: A robust CMS and web application framework for building versatile and scalable websites.
13. Web Accessibility Testing:
    
    1. axe: A web accessibility testing tool that integrates with various browsers and developer tools.