Worked on the kenzok8/sublink-worker repository to deliver a feature enabling custom traffic routing based on source IP CIDR rules. The implementation introduced initial support for CIDR-based routing, allowing users to define granular policies that direct traffic according to specific source IPs or CIDR ranges. Enhancements included protocol handling and robust processing for null values, improving both flexibility and operational safety. The work was delivered incrementally through two commits to ensure traceability and safer deployment. JavaScript and Node.js were used throughout, with a focus on full stack development and testing to ensure the new routing logic integrated smoothly with existing systems.