Ensuring quality in offshore custom software development involves several key practices, including rigorous vendor selection, establishing clear communication channels, and implementing a robust quality assurance process. Companies should partner with vendors with proven track records and expertise in the required technologies. Regular meetings, status updates, and using project management tools can help maintain alignment and transparency. Moreover, involving quality assurance teams from the start ensures that the code is tested and reviewed consistently, meeting the required standards and delivering a product that aligns with business objectives.