| MongoDB | MySQL | |
|---|---|---|
| Maintainer | MongoDB, Inc. | Oracle Corporation |
| First release | 2009 | 1995 |
| License | SSPL | GPLv2 (dual licensing) |
| Learning curve | Easy to start. Documents map naturally to application objects; data modeling discipline is what separates good deployments from painful ones. | Gentle, the classic starter relational database, with decades of tutorials and every framework supporting it first. |
| Performance | Fast document reads and writes with horizontal sharding built into the core; multi-document transactions exist but cost more than their SQL equivalents. | Excellent for read-heavy OLTP; InnoDB is solid and its replication is battle-tested at planet scale (YouTube via Vitess). |
MySQL guarantees relational integrity for structured business data; MongoDB trades that rigor for schema flexibility and horizontal scaling. Orders, payments and anything with strict relationships belong in MySQL (or PostgreSQL); catalogs, profiles, events and fast-evolving models suit MongoDB. Many real systems use one of each.