Full-Stack Node.js Developer - Code Review, Optimization, Security, Payment Integration, Deployment

We are seeking an experienced and skilled Full-Stack Node.js Developer to help us optimize, enhance, and secure our existing web application. The project involves a full code review, performance optimization, design improvements, and integration with various services such as email, payment gateway, and authentication. Additionally, we require expertise in working with cookies, enhancing the database structure and optimizing queries.

Responsibilities:
- Perform a comprehensive code review and implement necessary improvements
- Optimize the application for better performance and response time
- Enhance login/authentication with best practices including captcha implementation and the use of cookies
- Implement design improvements to enhance user experience
- Conduct security checks and implement necessary enhancements
- Configure usage quota per user based on subscription and bundle
- Integrate email services for login OTP, forgot password, and payment-related emails
- Implement email verification and OTP authentication
- Integrate a payment gateway for secure transactions
- Enhance the database structure, indexing, and optimize queries if needed
- Setup DevOps and deployment pipeline for efficient deployment
- Provide recommendations and explore options for hosting and email services
- Provide API collections (Postman) with automated testing and use cases
- Remove file uploads from all forms, and have users upload one file on their profile.
- For the point above, currently users upload PDF file the system strips its contents processes it and destroys the file before sending back the response, I want to discuss the best options here for security like hash checking (VirusTotal for example) of if it is perfectly safe continuing in the current way (meaning ignoring the point above) or if there is an altogether different approach.

Requirements:
- Strong proficiency in Node.js and experience with EJS templating
- Solid understanding of web application development and best practices
- Experience in code optimization, security enhancements, and database optimization
- Familiarity with authentication mechanisms, captcha implementation, and email integration
- Knowledge of payment gateway integration, working with cookies, and DevOps practices
- Strong problem-solving and communication skills
- Attention to detail and ability to meet deadlines


Please note that the web application is almost ready and not yet published. We have a domain and an Autonomous Oracle DB. We would like the freelancer to provide recommendations and explore hosting and email services options before starting work.

If you have the skills and expertise to take our web application to the next level and provide improvements in code, performance, security, and database optimization, we'd love to hear from you. Please submit your proposal outlining your relevant experience, approach, timeline, and cost breakdown, including recommendations for hosting and email services.