Node js functions

I am looking for a Node.js developer with intermediate experience to help me with my project. The specific functionalities that I need for my project include user authentication, file uploading and downloading, and database integration. I have specific requirements for the programming language or framework to be used, and I am open to any language or framework. The ideal freelancer for this project should have intermediate experience in Node.js and be able to fix a few bugs in my Flutter app.