PostgreSQL, also known as Postgres, is a free and open-source relational database management system, emphasizing extensibility and technical standards compliance. It is designed to handle a range of workloads, from single machines to data warehouses or web services with many concurrent users. Basically, Postgres has superpowers; capable of handling very large datasets as though it was smashing peanuts.
Now, you are wondering who could possibly need all that. Well, thanks to its superpowers, a lot of firms use it. Including top-rank companies like Netflix, Uber, Spotify and etc.