> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pulsy.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Storage and Messaging

> Explore the storage and messaging layers behind Atria.

# Storage and Messaging

Atria uses PostgreSQL for product metadata and NATS for event streams, block storage, leases, cursors, and chain state.

## PostgreSQL

PostgreSQL stores:

* Feeds.
* Outputs.
* Tags.
* Feed-output links.
* Deploy records.
* Status history.

## NATS JetStream and KV

NATS is used for:

* Feed deploy requests.
* Feed deployed events.
* Pause events.
* Feed result streams.
* Block data buckets.
* Chain state.
* Runtime and delivery leases.
* Feed cursors.

## High-Level Map

```mermaid theme={null}
flowchart TB
  Backend[Management backend] --> PG[(PostgreSQL metadata)]
  Orchestrator --> PG
  Ingestor --> KV[(NATS KV block data)]
  Runtime --> KV
  Runtime --> JS[(JetStream results)]
  Delivery --> JS
```

For feed result delivery, see [delivery](/atria/architecture/delivery).