Developed a new feature for the matomo-org/matomo repository, introducing a mechanism in the JavaScript tracker to cap the length of referral URLs stored in cookies. This enhancement addressed cookie overflow issues by implementing the setReferrerUrlMaxLength function, which allows configuration of the maximum referral URL length and ensures reliable cookie management. The work included integrating this setting into the tracker’s configuration and adding comprehensive unit tests to validate both the truncation logic and configuration behavior. By focusing on JavaScript, cookie management, and web tracking, the solution improved data quality and aligned with privacy requirements across diverse deployment environments.