Reviewed by Aditya Kumar · Last reviewed 2026-03-24
**Schema flexibility**: Document (MongoDB), key-value (Redis), wide-column (Cassandra), graph (Neo4j). **Scaling**: Horizontal sharding; eventual consistency. **Why NoSQL**: High write throughput; flexible schema; access-pattern optimization. **Trade-offs**: No ACID across...
Schema flexibility: Document (MongoDB), key-value (Redis), wide-column (Cassandra), graph (Neo4j). Scaling: Horizontal sharding; eventual consistency. Why NoSQL: High write throughput; flexible schema; access-pattern optimization. Trade-offs: No ACID across documents; limited joins; operational complexity. When to use: Session store (Redis); events (Cassandra); recommendations (Neo4j). Cost: Lower ops for schema-less; higher dev cost for modeling.
Red Flag: Choosing NoSQL because it's 'modern'—use when access pattern fits. Pro-Move: 'We moved session data from PostgreSQL to Redis—read latency dropped from 50ms to 2ms; PostgreSQL freed for transactional workloads.'
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