Full-stack developer needs to be proficient in both front-end and back-end technologies to build a complete web application. Below is a breakdown of a typical tech stack for a full-stack developer:

Front-end:

1. HTML/CSS: The building blocks of web development.
2. JavaScript: Essential for client-side scripting. Frameworks and libraries like React, Angular, or Vue.js are commonly used.
3. CSS Preprocessing: Sass, Less
4. Version Control/Git: Helps you to track changes, revert to previous stages, and work on different branches simultaneously.
5. Responsive Design: Bootstrap, Materialize, your own media queries, or other methods.
6. Build Tools: Webpack, Gulp, Grunt.
7. Package Managers: npm, yarn.

Back-end:

1. Server-side Languages: Node.js, Python (Django or Flask), Ruby on Rails, Java (Spring), PHP, etc.
2. Database Management: MySQL, PostgreSQL, MongoDB, etc.
3. Server Management: Understanding of how to manage a server using technologies like AWS, Heroku, or similar.
4. APIs: RESTful services or GraphQL.
5. Authentication: OAuth, JWT.
6. Web Servers: Nginx, Apache, among others.

DevOps:

1. Containerization: Docker
2. Orchestration: Kubernetes
3. Continuous Integration and Continuous Deployment (CI/CD): Jenkins, Travis CI, GitLab CI, etc.

Soft Skills:

1. Problem-Solving: Fundamental to any form of programming.
2. Version Control: Experience with Git is often considered essential.
3. Communication: Clear communication with team members, management, and sometimes clients is crucial.
4. Project Management: Familiarity with methodologies like Agile or Scrum can be helpful.