YugabyteDB is an open-source distributed SQL database designed for internet-scale, geo-distributed applications, combining the features of PostgreSQL and NoSQL systems. It provides a familiar programming and architectural model, eliminating complexities. The database is deployed over multiple machines, typically referred to as nodes, which are logical layers - Yugabyte Query Layer and DocDB. Each node has two main processes: YB-TServer ( Tablet Server) and YB-Master (Master Server), responsible for serving queries, automatic sharding, replication, transactions management, and storing system metadata. A cluster is a group of nodes that run together, providing high availability and load balancing. The universe is comprised of one primary cluster and multiple optional read replica clusters. Data in YugabyteDB is split into tablets, which are shards and spread over multiple nodes, automatically sharded with the help of hashing functions. Replication and storage use Raft protocol for strong consistency and DocDB's local storage engine is a customized version of RocksDB. Compared to PostgreSQL and MongoDB, YugabyteDB offers horizontal write scalability, global distribution, and fully relational SQL features like JOINs, referential integrity, and multi-table transactions, making it suitable for large-scale applications requiring high performance and availability.