The term “All Stack Developer” is not a widely recognized or standard job title in the field of software development. It is possible that you meant “Full Stack Developer,” which is a well-established role in the industry. 

Assuming you are referring to a Full Stack Developer, a Full Stack Developer is someone who has expertise in both front-end and back-end web development. They are capable of working on all aspects of a web application, from designing and building the user interface (UI) to developing the server-side logic, APIs, and managing databases. Here are the key responsibilities and skills of a Full Stack Developer:

Front-End Development:

1. HTML/CSS/JavaScript: Proficiency in front-end technologies for creating and styling web pages, adding interactivity, and enhancing the user experience.
2. Responsive Design: Ensuring web applications are responsive and work well on various devices and screen sizes.
3. Front-End Frameworks and Libraries: Knowledge of front-end frameworks and libraries like React, Angular, or Vue.js for building dynamic and interactive UIs.
4. State Management: Understanding and implementation of state management tools and patterns like Redux (for React) or Vuex (for Vue.js).

Back-End Development:

1. Server-Side Programming: Proficiency in a server-side programming language (e.g., Node.js, Python, Ruby, Java, C#) for implementing server logic and APIs.
2. Back-End Frameworks: Knowledge of back-end frameworks like Express.js (for Node.js), Django (for Python), Ruby on Rails, Spring Boot (for Java), or ASP.NET (for C#).
3. Database Management: Skills in working with databases, both relational (e.g., MySQL, PostgreSQL) and NoSQL (e.g., MongoDB).
4. API Development: Building RESTful APIs or GraphQL endpoints to enable communication between the front-end and back-end.