During January 2025, Hego focused on improving environment variable handling in the resend/react-email repository. He addressed a bug in the Email Template Preview feature, ensuring that the preview process now respects the user’s NODE_ENV configuration rather than defaulting to development mode. This change required careful adjustment of the environment variable merge logic within the Node.js CLI, using TypeScript to maintain type safety and reliability. By aligning the preview environment with user settings, Hego reduced confusion for developers and QA teams, resulting in more predictable and stable email template validation. The work demonstrated attention to detail in CLI development and configuration management.