A complete guide to MongoDB in Kotlin — the official MongoDB Driver, MongoClient connections, CRUD with BSON and data classes, filters and projections, aggregation pipelines, indexes, multi-document transactions, KMongo as an idiomatic alternative, and when to choose MongoDB.
A complete guide to Elasticsearch in Kotlin — index and mapping concepts, the Elasticsearch Java Client, document indexing, full-text search, query DSL, aggregations, filters, highlighting, bulk indexing, synchronization patterns with a primary database, and production tips.