React developer to work on existing code

I'm searching for a proficient progressive web app (PWA) developer who can assist in making my web app compatible with both desktop and mobile platforms.

Essential tasks:

- Inclusion of key functionalities like user authentication, real-time updates, and offline accessibility utilizing web sockets.
- Make the web app compatible on multiple platforms (i.e., Desktop, Mobile).
- Implement the already prepared codebase.

Ideal Skills and Experience:

A successful freelancer for this project should have extensive experience with:

- PWA development and making web apps cross-platform compatible.
- Implementing user authentication, real-time updates, offline accessibility, and utilizing web sockets in a PWA.
- Working with pre-existing codebases and adapting them to new projects.