Full stack developer is someone who has the knowledge and ability to develop/work on all layers of web application development. When a user clicks on a web page to perform some action, the webpage communicates with server which accesses a database and retrieves information to be sent back to the user. Easier said than done.
The web application development consists of many layers. You have the server that resides on an operating system, a database where the data gets stored, a front end which the user sees when he/she opens a website and a backend layer that communicates between front end and the server. There is also the work of gathering requirements, meeting with clients, creating documentation and project management.
For instance, consider a web page(s) where:
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