Cognee is a data-to-memory pipeline: a relational store preserves sources and provenance, a vector store finds semantically similar content, and a graph store represents entity relationships, exposed through remember, recall, improve, and forget.
Private-corpus sync is not periodic refetching. It requires stable canonical IDs, source versions plus checksums for change detection, idempotent upserts, and tombstones that propagate deletion through every index.
Kafka is a distributed log ordered by partition and retained by policy. Consumer groups divide work through offsets, while exactly-once processing holds only inside boundaries covered by Kafka transactions.
Apify is not a single crawler. It packages scraping programs as Actors, saves reusable configurations as Tasks, triggers them with Schedules, and delivers results through Datasets. It fits teams that do not want to operate queues, schedulers, and workers, but Actor fees, compute, proxies, storage, and transfer all draw from the same platform budget.