Comprehensive QA Testing for Flutter-Based App

I require an expert in QA testing to rigorously evaluate my mobile app and its backend. This individual will be tasked with:

- User Interface (UI) testing: To ensure that the app's interface is user-friendly and operates smoothly.
- Functionality testing: To ascertain that all features of the app perform as intended while making sure all bugs and glitches are identified and documented.
- Performance testing: To guarantee that the app performs well under various conditions which includes stress testing, stability testing, and load testing.

While I can provide limited access to the source code and documentation, I expect the freelancer to have in-depth understanding of Flutter and Golang, as these were the primary technologies used in the development of this project. Both Android and iOS versions of the app must be comprehensively tested.

Ideal Skills:
- Expert knowledge of Flutter and Golang
- Proven experience in UI, functionality and performance testing
- Familiarity with both Android and iOS app testing.