## TL;DR

MongoDB is a document-oriented NoSQL database first released in 2009 by MongoDB Inc. (formerly 10gen). Instead of tables and rows, it stores data as JSON-like BSON documents in collections, with a flexible schema. As of May 2026, MongoDB has 28,333 GitHub stars and is one of the most popular NoSQL databases, used by companies including Uber, eBay, and Bosch. MongoDB 8.0 (2024) is the current major release.

## Core Concepts

- **Document**: JSON/BSON record — the equivalent of a row in SQL
- **Collection**: Group of documents — the equivalent of a table
- **Indexes**: B-tree, text, geospatial, TTL — same purpose as SQL indexes
- **Aggregation Pipeline**: Multi-stage data processing (filter, group, join, transform)
- **Replica Set**: Primary + secondaries for high availability
- **Sharding**: Horizontal scaling across clusters

## Further Reading

- [MongoDB Docs](https://www.mongodb.com/docs/): Official documentation
- [MongoDB GitHub](https://github.com/mongodb/mongo): Source code (28K+ stars)