> ## 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.

# API reference

> Interface reference for IXO Protocol gateways and IXO application services.

This section documents API interfaces only. It does not define protocol concepts, product positioning, or canonical endpoint literals.

For a **single comparison table** (read/write, purpose, links to auth and endpoints), start at [API introduction](/api-reference/intro-apis).

## API surfaces

<CardGroup cols={2}>
  <Card title="Blockchain RPC API" href="/api-reference/rpc-api" icon="server">
    Direct node-level interface for IXO Protocol transaction and state access.
  </Card>

  <Card title="Blockchain REST API" href="/api-reference/grpc-gateway-api" icon="cloud">
    HTTP/JSON gateway over gRPC query services for IXO Protocol modules.
  </Card>

  <Card title="IXO Blocksync GraphQL API" href="/api-reference/blocksync-graphql-api" icon="compass">
    Indexed query interface for chain data through IXO Blocksync.
  </Card>

  <Card title="Matrix state bot API" href="/api-reference/matrix-state-bot-api" icon="snowflake">
    Service API for state and ACL operations in IXO Matrix rooms.
  </Card>

  <Card title="Registry API" href="/api-reference/registry-api" icon="database">
    Application API for Impact Hub Registry service workflows.
  </Card>

  <Card title="USSD gateway API" href="/api-reference/ussd-api" icon="tower-cell">
    Session endpoint for the IXO USSD gateway — accepts input from telecom gateways and returns USSD responses.
  </Card>
</CardGroup>

## Boundary between protocol and services

* IXO Protocol APIs: `rpc-api` and `grpc-gateway-api`.
* Service APIs: `blocksync-graphql-api`, `matrix-state-bot-api`, and `registry-api`.
* Protocol concepts and module behavior belong in protocol documentation, not API operation pages.

## Shared references

<CardGroup cols={3}>
  <Card title="Networks and endpoints" href="/reference/networks-and-endpoints">
    Confirm canonical endpoint mappings by network and environment.
  </Card>

  <Card title="Authentication matrix" href="/reference/authentication-matrix">
    Verify interface-specific authentication requirements and literals.
  </Card>

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

## Related API guidance

<CardGroup>
  <Card title="Authentication" href="/api-reference/authentication" icon="shield">
    Compare authentication schemes by API surface.
  </Card>

  <Card title="Error handling" href="/api-reference/errors" icon="bell">
    Handle common API and transport failures.
  </Card>

  <Card title="Pagination" href="/api-reference/pagination" icon="rectangle-list">
    Use cursor and page patterns for large result sets.
  </Card>
</CardGroup>