Has anyone successfully built an e-commerce platform with MongoDB?

I’ve seen MongoDB used as a centralized product store in a service-oriented system. Teams owned separate portions of the product data, exchanged updates through Kafka, and the combined documents were stored in MongoDB. That architecture can work, but it requires careful ownership rules, message handling, indexing, and a clear plan for consistency.

For most e-commerce systems, PostgreSQL would be my default choice unless there’s a strong reason to use something else. MongoDB can be useful for flexible catalog data, but using it for every part of the system often creates operational and consistency problems. Inventory and order state are especially risky places to trade away relational guarantees.

It can work well if the data model and query patterns are understood before the system is designed. One e-commerce site used MongoDB to replicate product data from PostgreSQL and support autocomplete and search transformations. The database choice mattered less than designing around the actual read patterns and performance requirements.

MongoDB can make sense for product catalogs when different categories have very different attributes. Watches, jewelry, and handbags may all need completely different fields, so a document model can be convenient. Inventory, orders, payments, and other transactional workflows are a different story, though. Those usually need strong consistency and are easier to manage in a relational database. A common compromise is MongoDB for catalog and content data, with MySQL or PostgreSQL handling orders and inventory.

A large marketplace I worked with used a hybrid setup. Core relational data lived in PostgreSQL, while some flexible listing data was stored in NoSQL. In practice, anything needed to meet strict search latency requirements eventually had to be moved into proper columns or separate search-oriented tables. The NoSQL data became more of a temporary dumping ground than a solution for important, frequently queried fields.