Backend Completion for Web Project

I need an experienced backend developer to complete several functionalities for my project, which is currently partially built using bolt.new. The project needs to be completed within 3 weeks.

Key requirements include:
- Database integration
- API development
- User authentication

The current backend is built with a language other than Node.js, and frontend React, and is using a database type that is also 'other'.

Ideal skills and experience:
- Strong background in backend development
- Proficiency in database integration and API development
- Experience with user authentication processes
- Ability to work with various programming languages and database types
- Proven track record of delivering projects on time

Please provide examples of previous similar work and confirm your availability for the 3-week timeline.