Worked on MetaMask/metamask-mobile to enhance reliability for ERC20 token transactions on custom networks, focusing on front end development with React and TypeScript. Addressed a bug in the ERC20 sending flow by introducing optional chaining, which prevents errors when accessing token addresses on non-standard networks and improves transaction success rates. Improved the unit testing framework by restructuring enabled network data into a map, resulting in clearer and more maintainable tests. These updates reduced user-facing errors and strengthened test coverage, reflecting a methodical approach to code quality and maintainability while leveraging TypeScript and unit testing best practices throughout the process.