Developed an inventory management enhancement for the labd/commercetools-node-mock repository, focusing on the new removeQuantity action for inventory entries. This feature enables accurate stock deduction while enforcing non-negative inventory levels through built-in guardrails. The implementation leveraged TypeScript for backend logic and comprehensive unit testing, ensuring that quantity updates behave as expected and preventing negative stock scenarios. Detailed documentation and changesets were provided to support integration and developer understanding. By improving the fidelity of inventory simulations, this work enhanced the reliability of merchant testing and downstream integration validation, contributing to a more robust and realistic API development environment.