The core time series engine, called cesium (https://github.com/synnaxlabs/synnax/tree/main/cesium), is written completely from scratch. It's kind of designed as a "time-series S3", where we store blobs of samples in a columnar fashion and index by time. We can actually get 5x the write performance of something like InfluxDB in certain cases.

For other meta-data, such as channels, users, permissions, etc. we rely on CockroachDB's Pebble, which is a RocksDB compatible KV store implemented in pure go.