Apache Kafka vs Couchbase XDCR

Apache Kafka is an open-source distributed event-streaming platform for data pipelines, streaming analytics, data integration, and mission-critical applications. Applications can publish and subscribe to event streams, retain them durably, and process them either in real time or later. Kafka supports durable, fault-tolerant replication across availability zones, data centers, or geographic regions. Kafka Streams provides stateful operations, aggregations, windowing, joins, event-time processing, and exactly-once processing. Kafka Connect links hundreds of event sources and sinks, including Postgres, JMS, Elasticsearch, and AWS S3. Deployments can use bare metal, virtual machines, or containers, on premises or in the cloud, with self-managed or vendor-managed options. The project describes network-limited throughput, latency as low as 2 ms, and clusters of up to 1,000 brokers. Kafka is self-hosted, free, and open source under Apache License 2.0. A local quickstart requires Java 17 or later.

Couchbase XDCR is a web-based service for replicating database changes between clusters. It supports change data capture and bidirectional synchronization, allowing changes to move in both directions. The deployment model is hybrid. Couchbase lists plans with hourly per-node billing, cluster minimums, and backup intervals. Basic is $0.15 a month, billed from $0.15/hr per node, with a one-node minimum and a 24-hour backup interval. Developer Pro is $0.35 a month, billed from $0.35/hr per node, with a one-node minimum, three nodes for multiple cluster availability zones, and backup intervals up to one hour. Enterprise is $0.49 a month, billed from $0.49/hr per node, with a three-node minimum and backup intervals up to one hour. Couchbase Enterprise is $0.66 a month, billed from $0.66/hr per node through cloud marketplaces, and includes Couchbase Server 8. A Free plan is described as one node and 8GB, although the pricing facts mark no free plan. Couchbase was founded in 2011 and is headquartered in San Jose.