Over a two-month period, contributed to the dnhatn/elasticsearch and elastic/elasticsearch repositories by enhancing search capabilities and improving backend reliability. Developed support for nested fields in the Elasticsearch Term Vectors API using Java and YAML, enabling more accurate vectorization and search relevance for complex document structures. Focused on robust API development and unit testing to ensure maintainability. Additionally, addressed a bug in the caching layer by correcting cache key string representation, reducing the risk of stale data and improving query consistency. Demonstrated backend development expertise, attention to detail, and collaborative open-source practices through code review and co-authored contributions.