database-as-a-service
(4)
MongoDB
MongoDB escaped the rows-and-columns era by betting on flexible documents. Nearly two decades later, it is trying to become the memory, search engine and live data layer beneath the next generation of AI applications.
Couchbase
Couchbase is an enterprise NoSQL database company whose distributed, document-oriented platform powers low-latency, high-throughput applications for large organizations. Its flagship products - Couchbase Server, the fully managed Capella database-as-a-service, and Couchbase Mobile/Lite for edge and offline use - combine key-value speed, JSON flexibility, SQL-style querying (SQL++/N1QL), full-text and vector search in a single system. Founded in 2009 and long a rival to MongoDB, Couchbase went public on Nasdaq in 2021 and was taken private by Haveli Investments in a $1.5 billion deal in September 2025.
PlanetScale
PlanetScale is a San Francisco database company that turns the hard parts of running relational databases at scale into a managed cloud service. Founded in 2018 by the creators of Vitess - the MySQL-sharding system built at YouTube and later used by Slack, GitHub and Square - the company sells a serverless database platform known for non-blocking schema changes, branching workflows borrowed from Git, and, more recently, Metal instances built on locally-attached NVMe drives. In 2025 it extended the same platform to Postgres, chasing the fastest-growing part of the database market while still, in its own words, loving MySQL.
Yugabyte
Yugabyte builds YugabyteDB, the open-source distributed SQL database designed for mission-critical cloud-native applications. Founded in 2016 by three ex-Facebook engineers who built Cassandra and HBase, Yugabyte combines full PostgreSQL compatibility with the horizontal scalability and fault tolerance of modern distributed systems. Deployed in 100+ countries and trusted by Fortune 100 companies including GM, Kroger, Shopify, and Charles Schwab, YugabyteDB handles over 1 million transactions per second while surviving node, zone, and region failures automatically. A $1.3B unicorn backed by Lightspeed and Sapphire Ventures, Yugabyte is the rare database company that made its entire core product fully open source - and built a thriving enterprise business around it anyway.