> ## 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.

# Introduction

> How to choose between IXO Protocol APIs and IXO service APIs.

Use this page to select the right **API surface** before implementation.

## Vocabulary

* **Protocol gateways** — Node-level interfaces to IXO Protocol modules: submit and query chain state via **JSON-RPC** or **REST over gRPC** (Cosmos stack). You typically need a wallet or signer for writes.
* **Service APIs** — Operator-hosted interfaces over **indexed chain data**, **Matrix**, **registry workflows**, or **USSD** sessions. Auth and base URLs are **deployment-specific**; never assume one header works everywhere.

## Comparison matrix

<AccordionGroup>
  <Accordion title="Blockchain RPC API" icon="server">
    * **Primary purpose:** Transactions, ABCI queries, Tendermint RPC
    * **Typical operations:** `broadcast_tx_*`, status, block, tx search
    * **Read / write:** Read + write (tx)
    * **Auth and endpoints:** [Authentication matrix](/reference/authentication-matrix); [Networks and endpoints](/reference/networks-and-endpoints)
    * **Docs:** [Blockchain RPC API](/api-reference/rpc-api)
  </Accordion>

  <Accordion title="Blockchain REST API (gRPC gateway)" icon="cloud">
    * **Primary purpose:** HTTP/JSON queries (and tx broadcast where exposed)
    * **Typical operations:** Module REST paths, Swagger/OpenAPI per deployment
    * **Read / write:** Read; write depends on deployment
    * **Auth and endpoints:** Same as RPC—confirm with node operator
    * **Docs:** [REST (gRPC gateway)](/api-reference/grpc-gateway-api)
  </Accordion>

  <Accordion title="IXO Blocksync GraphQL API" icon="compass">
    * **Primary purpose:** Indexed queries over chain-derived entities
    * **Typical operations:** GraphQL queries (subscriptions if enabled)
    * **Read / write:** **Read-only** in docs model
    * **Auth and endpoints:** Service operator credentials
    * **Docs:** [Blocksync GraphQL API](/api-reference/blocksync-graphql-api)
  </Accordion>

  <Accordion title="Matrix state bot API" icon="snowflake">
    * **Primary purpose:** Room state, ACLs, automation hooks for Matrix
    * **Typical operations:** Bot-specific HTTP endpoints
    * **Read / write:** Read + write (room operations)
    * **Auth and endpoints:** Service operator credentials
    * **Docs:** [Matrix state bot API](/api-reference/matrix-state-bot-api)
  </Accordion>

  <Accordion title="Registry API" icon="database">
    * **Primary purpose:** Impact Hub Registry application workflows
    * **Typical operations:** CRUD-style registry operations per spec
    * **Read / write:** Read + write (per spec)
    * **Auth and endpoints:** Often Basic or bearer—confirm matrix
    * **Docs:** [Registry API](/api-reference/registry-api)
  </Accordion>

  <Accordion title="USSD gateway API" icon="tower-cell">
    * **Primary purpose:** Telecom session bridge for USSD menus
    * **Typical operations:** Session request/response
    * **Read / write:** Write (session replies) + read patterns per spec
    * **Auth and endpoints:** Service operator policy
    * **Docs:** [USSD gateway API](/api-reference/ussd-api)
  </Accordion>
</AccordionGroup>

For SDK and product naming, see [Product and SDK map](/reference/product-and-sdk-map).

## API families (quick links)

* **IXO Protocol gateways**
  * [RPC API](/api-reference/rpc-api)
  * [REST (gRPC gateway)](/api-reference/grpc-gateway-api)
* **IXO service APIs**
  * [Blocksync GraphQL](/api-reference/blocksync-graphql-api)
  * [Matrix state bot](/api-reference/matrix-state-bot-api)
  * [Registry](/api-reference/registry-api)
  * [USSD gateway](/api-reference/ussd-api)

## Authentication and endpoints

This page does not define canonical auth headers or endpoint literals.

<CardGroup cols={3}>
  <Card title="Authentication matrix" href="/reference/authentication-matrix">
    Use canonical auth requirements and literals by interface.
  </Card>

  <Card title="Networks and endpoints" href="/reference/networks-and-endpoints">
    Confirm network-specific endpoint mappings before implementation.
  </Card>

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

## Next steps

<CardGroup cols={3}>
  <Card title="API index" href="/api-reference">
    Compare protocol and service interfaces from one entry point.
  </Card>

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

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