Qualified Ruby on Rails dev for SaaS - server/Stripe/users migration, & additional features

Looking for an experience RoR to make updates. We have a PM already who was involved with the original build and can guide specific bottlenecks, but the freelancer or agency still needs to be qualified to make suggestions, troubleshoot bottlenecks, and developer quickly.

The two main bottlenecks are our link redirect speeds, and migrating the existing platform to a new Stripe account, as well as adding a few new features before migrating users to the new server.

Specifically, we'll be moving from Heroku to AWS, migrating from one stripe to another, and the platform is built on RoR.

When applying, please provide specific experience you have with subscription-based software platforms, and the more experience you have specifically with AWS, RoR, & Stripe the better. If you do not provide any examples in your cover letter, you will not be ---------- ont-end experience, and basic JS (for our Chrome extension) are added benefits, but not necessarily mandatory if you excel at all other requirements.

The app is live for 1.5 years and has active users.