As an experienced full-stack developer, I have a deep understanding of the technologies involved in your project: React, Node.js, Express, and React Native. Throughout my 7-year journey in mobile and web development, I have not only created scalable applications but also kept them up-to-date with the latest stable versions, just as yours needs an upgrade. Fluent in MySQL and PHP, I am confident to efficiently upgrade your framework while ensuring a seamless transition to the new versions.
Moreover, I am no stranger to integrating third-party APIs and services - a skill paramount for your Membership Platform's smooth functioning. Previously, I've successfully implemented payment gateways like Braintree and PayPal (which are used by you presently), email automation using AWS (transmail), Zendesk for comprehensive support solutions, MailerLite for synchronizing member data and more.
Lastly, signing off with three words to sum up why I'm the best fit: reliability, dedication, and quality. Rest assured that apart from adhering to an attractive pricing model, maintaining clear communication and meeting deadlines would be my priority throughout this project. So let's create - or should we say 'upgrade' - something great together!