NodeJS Code Review & Enhancements

I am looking for an experienced NodeJS developer to perform a code review and make necessary improvements to a NodeJS application. The ideal candidate will also have experience with the Google Firebase database API, as this is used extensively in the application. The purpose of this app is to provide a range of web services that are used by a client application which uses the Unity Game Engine. Unity programming experience is not required, but may be a helpful bonus. The application is currently fully functional and provides a REST API with 44 web services for an online game server. All services have been tested to an extent and under normal use by the Unity client application already provide the correct responses as well as a range of error states. However, the NodeJS application was rapidly prototyped to provide the required game functionality as a primary priority, meaning that little consideration was given to matters of security, cheat prevention and overall performance optimisation. The game and server are still in development and are not currently available for public use, though it is intended to move the project into a public beta shortly, making it vital that the online components of the system are nearer to production-ready and will prove both ourselves and our users with an acceptable level of security. The required improvements are likely to include some or all of the following: - Security enhancements - Processing speed optimisations, specifically related to methods that access the Firebase database multiple times - Prevention of errors caused by invalid request parameters It is hoped that the approach taken for some of these enhancements should be able to be scaled across the 44 services relatively easily, though it is possible that a degree of refactoring may be required for all service methods. It is difficult to reasonably estimate the work required, therefore I am happy to negotiate or consider extending the work based on the recommendations and findings of the developer once they commence working on the project. Candidates for this project must have: - Excellent JavaScript programming ability - A strong knowledge of web based application requirements, including security requirements - Prior NodeJS experience and ideally, prior Google Firebase experience - Good communication skills with a techical and conversational level of English - The ability and availability to deliver the agreed work within a reasonable time Proposals must include the following: - Your level of experience with web development, JavaScript, NodeJS (specifically) and Google Firebase - 3 links or references to your previous work relating to the above skills - (Optional, but preferred) An excerpt of NodeJS code developed by you to demonstrate your level of experience Unfortunately, proposals that do not meet these minimum requirements will not be considered. Thank you for taking the time to read this posting and I look forward to receiving your proposal.