---
title: "Statement Store Method Group"
description: "TrUAPI method group for publishing and subscribing to gossip-distributed signed statements on the People Chain through the Host and SDK client."
categories: "Apps, Reference"
url: "https://developers.polkadot.com/reference/apps/protocol/truapi/statement-store/"
word_count: 417
token_estimate: 647
version_hash: "sha256:be606c01f3bf21444544c8e30c07914a2d11f23e936340f209674caa8a69371d"
last_updated: "2026-11-13T11:04:04+00:00"
---

# Statement Store

## Introduction

The Statement Store method group lets a Product publish and subscribe to signed, gossip-distributed statements on the People Chain. The Statement Store itself, including the pallet, gossip layer, lifecycle, and validation rules, is a network-layer pub/sub primitive. It is short-lived, allowance-gated, and propagated peer-to-peer. This TrUAPI group is how a Product reaches it through the Host.

The Product SDK wraps this surface as `StatementStoreClient` from [`@parity/product-sdk-statement-store`](https://www.npmjs.com/package/@parity/product-sdk-statement-store). For the conceptual model of what statements are good for (versus the Bulletin Chain or local storage), see [Where to Store Data](/apps/concepts/data-placement/).

## Conceptual Contract

The group exposes the standard pub/sub surface with the Host filling in the parts a Product cannot do safely on its own:

- **Publishing a statement**: The Product hands the Host a payload (under the per-statement 512-byte limit), a topic, a channel, a time to live (TTL), and any options. The Host requests an authentication proof from the paired App, attaches the per-Product account context and primary topic (`blake2b(appName)`), and submits to the People Chain node's `statement_submit` JSON-RPC.
- **Subscribing to a topic filter**: The Product registers a callback for statements matching its primary topic plus any secondary `topic2`. The Host opens the underlying `statement_subscribeStatement` JSON-RPC, decodes payloads, and deduplicates by content hash before invoking the callback.
- **Channel-based last-write-wins**: When a statement carries a `channel`, the pallet replaces older statements from the same account on the same channel. The SDK abstracts this as `ChannelStore<T>` on top of the underlying method group.

Delivery is best-effort gossip, with no retry, acknowledgment, or ordering guarantee. Reliability is composed at the application layer. For example, if a recipient needs to confirm receipt, they publish an acknowledgment statement back.

For the Desktop-side mediation perspective, see [Statement Store via Host API](/reference/apps/hosts/polkadot-desktop/statement-store/).

:::caution[Provisional]
Detailed error taxonomy, allowance-management primitives, and any direct topic-walking API remain provisional.
:::

## Where to Go Next

<div class="grid cards">

- **Exchange Ephemeral Messages**

    ---

    The Product-side how-to: setting up the client, subscribing, publishing typed statements, and using channels.

    [→ Get Started](/apps/build/pub-sub-off-chain-data/)

- **Statement Store via Host API**

    ---

    What Polkadot Desktop adds when mediating Statement Store traffic, including proof routing, account context, and per-Product topic scoping.

    [→ Reference](/reference/apps/hosts/polkadot-desktop/statement-store/)

</div>