> ## Documentation Index
> Fetch the complete documentation index at: https://ixoworld-mintlify-9a7944b6.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Blockchain RPC API

> Node-level API interface for IXO Protocol transactions and state queries.

This page documents the RPC interface family for IXO Protocol. It does not document application service APIs such as Impact Hub Registry, IXO Blocksync, or IXO Matrix.

## Overview

* Use this interface for protocol-level operations against chain nodes.
* Prefer this when you need direct interaction with IXO Protocol modules.
* For indexed or application-service workflows, use service APIs in this section instead.

## Protocol boundary

* In scope: chain state queries and transaction submission patterns.
* Out of scope: service-specific business endpoints and off-chain workflow APIs.

## Authentication and endpoints

Authentication depends on node and deployment policy.

* Check `/reference/authentication-matrix` for active auth requirements.
* Check `/reference/networks-and-endpoints` for network-specific RPC endpoints.

## Example message shapes

```protobuf theme={null}
message MsgCreateEntity {
  string creator = 1;
  string entity_type = 2;
  string entity_status = 3;
}
```

```protobuf theme={null}
message MsgSubmitClaim {
  string creator = 1;
  string collection_id = 2;
  string claim_id = 3;
}
```

## Troubleshooting

* **`connection refused` / TLS errors** — Wrong host, port, or TLS termination. Confirm the literal in [Networks and endpoints](/reference/networks-and-endpoints) and your operator’s current RPC URL.
* **`invalid JSON-RPC` / parse errors** — Request body not valid JSON-RPC 2.0; include `jsonrpc`, `id`, `method`, and `params` as required by the method.
* **Transaction broadcast failures** — Inspect `code`, `codespace`, and `rawLog`. Common causes: insufficient fees, wrong `chain-id`, sequence mismatch, or missing signer permissions. See [Error handling](/api-reference/errors) and [Claims management](/guides/dev/ixo-claims#troubleshooting).
* **Auth on RPC** — Many nodes allow unauthenticated read; writes require a valid signed tx, not an API key. Confirm policy in [Authentication matrix](/reference/authentication-matrix).

## Related references

<CardGroup cols={3}>
  <Card title="Blockchain REST API" href="/api-reference/grpc-gateway-api">
    Access protocol queries over HTTP/JSON through the gRPC gateway.
  </Card>

  <Card title="IXO Blocksync GraphQL API" href="/api-reference/blocksync-graphql-api">
    Query indexed chain data through the IXO Blocksync service layer.
  </Card>

  <Card title="Product and SDK map" href="/reference/product-and-sdk-map">
    Navigate IXO products, APIs, and SDK references.
  </Card>
</CardGroup>