multi‑core‑indexer is a Node.js library that continuously indexes the entries of one or more Hypercore logs, persisting its progress so it can resume after restarts. It streams downloaded blocks to a user‑provided `batch` callback, supports sparse and unordered cores, and lets developers add or remove cores at runtime—making it useful for applications that need to build searchable or processed indexes over multiple Hypercore datasets. It is aimed at developers building decentralized data pipelines or search services on top of the Hypercore protocol.