(algolia employee) Hi Chris, Algolia is actually not using Elasticsearch. We've been building our own search engine from the ground up to target the very (end-)user-facing search use-case (big focus on UX, speed & typo-tolerance) while one of Elasticsearch's sweet spot is more billion of line of logs indexing, aggregations & filtering.

You can read more about the differences on Quora, our CTO answered there a few years ago: https://www.quora.com/How-does-Elasticsearch-relate-and-or-c...