During January 2025, Hego focused on improving environment configuration 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 setting rather than defaulting to development mode. This required refining the environment variable merge logic within the CLI development workflow, using TypeScript and Node.js to implement the fix. By aligning the preview environment with user configurations, Hego enhanced reliability and reduced confusion for developers and QA teams. The work demonstrated careful attention to environment management and contributed to more predictable and stable email template validation.