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

# Storage and messaging platform

> Durable state, asynchronous delivery, and binary asset storage in Harmonia.

## How Harmonia uses it

Firestore owns tenant-scoped workflow truth and atomically records stage outbox entries. Pub/Sub transports stage triggers but cannot advance state by itself. Cloud Storage holds uploaded and generated binary assets while Firestore retains identity, lineage, and digests.

<CardGroup cols={2}>
  <Card title="Firestore" href="/platform/data/firestore">Durable records and transactions.</Card>
  <Card title="Pub/Sub" href="/platform/data/pubsub">At-least-once stage delivery.</Card>
  <Card title="Cloud Storage" href="/platform/data/cloud-storage">Authorized source and output assets.</Card>
</CardGroup>

## Evidence status

Emulator and contract tests verify local persistence behavior. Cloud resource existence and production data paths require authenticated infrastructure evidence.