MERN Stack Backend Developer Needed

I'm looking for a skilled MERN stack developer to build a robust backend with of Scalable, Efficient, fast , api-first and modular design. It should follow SOLID principle and MVC structure, that can scale to millions of users . I already have a working product. Now I want it to make it robust.

Key Features:
- Session management
- modular implementation of features
- support internationalisation(multi language)
- create option to handle multiple admin, multiple departmentartization.
- Implementing CRUD operations for user data.
- Establishing User Authentication and Authorization systems
- Developing User Profile Management capabilities, and other special profile management

Ideal candidates should have a strong background in building with the MERN stack, specifically focusing on backend development.