Comprehensive Node.js Web Application Development

I am seeking a proficient Node.js developer to work on several key components of my project. My aim is to build a robust web application involving three different areas:

1. Backend Development: This forms the crux of my project. Solid experience in crafting efficient server-side software is essential. You should ideally have a strong knack for building robust architectures.

2. API Development: I need a skilled hand in API creation and management. You should have a history of delivering APIs with high availability and low latency.

3. Real-Time Applications: My project also seeks to incorporate real-time functionality, opening the need for experience in creating such applications.

For the web application, we have clear objectives:

- User Authentication: Implementing state-of-the-art authentication protocols to ensure secure access. Your ability to work with OAuth or JWT would be beneficial.

- Database Integration: The developer should be well-equipped to integrate databases. Any previous experience dealing with SQL or NoSQL databases would be highly valued.

- Payment Gateway Integration: Equally critical is the integration of a reliable payment gateway. Previous eCommerce experience is a bonus, but the ability to work with popular APIs like Stripe or PayPal is essential.

Please place your bid if you are a confident Node.js developer with a reliable track record in these areas.