Couchbase
What it is: Distributed NoSQL database combining key-value, document, and full-text search. Built for interactive applications with sub-millisecond latency.
What It Does Best
Memory-first architecture. Managed cache layer built-in. Automatic data tiering between memory and storage.
Mobile sync. Couchbase Lite for offline-first mobile apps. Bi-directional sync when online.
SQL-like queries. N1QL query language. JSON documents with familiar SQL syntax.
Pricing
Community Edition: Free, limited features. Enterprise: contact sales. Capella (cloud): usage-based, ~$0.25/hour per node.
When to Use It
✅ Mobile and edge applications
✅ Session stores and caching with persistence
✅ Real-time gaming and collaboration apps
✅ Offline-first applications
When NOT to Use It
❌ Simple CRUD apps (overkill)
❌ Complex analytics (use data warehouse)
❌ Strong relational data requirements
Bottom line: Best choice for mobile-first apps needing offline capabilities. Built-in caching makes it fast. Less popular than MongoDB, but mobile sync is killer feature. Consider for edge computing scenarios.