1. Storage and Collaboration: Glitch provides unlimited storage for projects, allowing users to work on larger projects without worrying about space limitations. Additionally, Glitch has built-in collaboration features that make it easy for multiple users to work together on the same project, with real-time updates and communication. In contrast, repl.it has limited storage space and does not offer built-in collaboration features, making it more suitable for smaller projects worked on individually.

2. Programming Language Support: Glitch supports a wide range of programming languages, including HTML, CSS, JavaScript, Python, and more. This makes it a versatile platform for developing different types of projects. On the other hand, repl.it also supports multiple programming languages, but it has a stronger emphasis on educational programming languages like Python, Java, and JavaScript. It provides a more beginner-friendly environment with helpful features like step-by-step debugging and interactive consoles.

3. Deployment Options: Glitch allows users to easily deploy their projects as web applications. With a simple click, projects can be published and accessed online, making it convenient for showcasing and sharing projects with others. On the contrary, repl.it primarily focuses on the development and execution of code, and does not have a direct deployment feature integrated into the platform.

4. Community and Resources: Glitch has a vibrant and active community wherein users can share their projects, explore other projects, and collaborate with other developers. It also provides a vast library of community-built starter projects and code snippets that users can utilize to kickstart their own projects. Repl.it also has a community aspect, but it may not be as extensive as Glitch's. However, repl.it offers a comprehensive built-in documentation system and resources for beginner programmers, making it a valuable learning resource.

5. IDE Functionality: Glitch offers a full-fledged integrated development environment (IDE) that includes various useful features like a built-in terminal, console, and live preview. These features allow developers to test and debug their code efficiently within the same environment. Repl.it also provides an IDE with similar features, but it offers additional functionalities for educational purposes, such as code challenges and interactive tutorials.

In Summary, the key differences between Glitch and repl.it lie in their storage and collaboration capabilities, programming language support, deployment options, community and resources, and IDE functionality.