neondatabase/neon

Neon is an open-source platform that runs Postgres, a widely used relational database, as a serverless service. The README explains its core idea: it separates the part that answers queries (compute) from the part that stores data (storage). In a normal Postgres setup these two responsibilities live together on the same machine, which makes it hard to scale them independently. Neon splits them apart so compute can grow, shrink, or pause without disturbing the data, and the data lives in a separate storage engine that spreads itself across a cluster of nodes. That storage engine has two pieces. A component called the Pageserver acts as the durable backend for the database pages. A second component called the Safekeepers form a redundant log service that receives Postgres's write-ahead log (the running record of every change) from the compute node and holds it safely until the Pageserver has processed it and uploaded it to cloud storage. The compute nodes themselves are stateless Postgres servers backed by that storage engine. Because state lives in storage rather than compute, the description notes you get autoscaling, code-like database branching (cheap, fast copies of a database, in the spirit of git branches), and the ability to scale compute down to zero when idle. You would use Neon when you want regular Postgres without managing a server: prototypes that go quiet, preview environments that need their own database per branch, or apps with spiky traffic. It is written in Rust, ships with a patched Postgres, and offers a hosted free tier as well as instructions for building and running the stack locally.