The article presents the PolarDB library of structured data manipulation tools, created in the Institute of Information Systems of the SB RAS. It is designed to construct systems for structuring, storing and processing data, including data of large volume. The library is built on the previously developed recursive typing system and covers a number of essential tasks, such as data structuring, serialization, data mapping to byte streams, index constructions, block implementation of dynamic byte streams, data distribution and data processing, backup and recovery. PolarDB library allows users to create effective solutions for specialized databases in different paradigms: sequences, relational tables, storage key-value, graph structures.