Sebastian worked on the vechain-sdk-js repository, focusing on backend development and unit testing using JavaScript and TypeScript. During this period, he addressed a precision issue in the AccountsModule’s energy value tests by refactoring the numeric handling from floating-point to BigInt. This technical change improved the accuracy of energy comparisons, particularly for large or fractional values, and reduced test flakiness in continuous integration. By stabilizing the unit tests, Sebastian reinforced the reliability of energy accounting within the SDK. His work contributed to more maintainable code and smoother release cycles, demonstrating depth in backend problem-solving and test-driven development practices.