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

# Introduction

> On/off-ramps and swaps — buy and sell stablecoins and yield-bearing stablebonds with fiat, or swap one asset for another.

<Info>
  **Build against the sandbox first.** Every example in these docs works against `https://api.sand.etherfuse.com` with no real money or personal data. Start with the [Quickstart](/quickstart).
</Info>

## Get started

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Get a sandbox key and make your first authenticated call in a few minutes.
  </Card>

  <Card title="Initial setup" icon="flask" href="/initial-setup">
    Create a sandbox account, generate API keys, and learn the base URLs.
  </Card>

  <Card title="Onboard a customer" icon="user-check" href="/guides/onboarding">
    Run KYC and link bank accounts via hosted UI or the programmatic API.
  </Card>

  <Card title="API Reference" icon="code" href="/api-reference/lookup/list-stablebonds">
    Browse all endpoints with live "Try it" requests and code samples.
  </Card>
</CardGroup>

## What you can build

<CardGroup cols={3}>
  <Card title="Onramp" icon="arrow-up-right-dots" href="/guides/testing-onramps">
    Customer pays fiat, receives tokens in their wallet.
  </Card>

  <Card title="Offramp" icon="arrow-down" href="/guides/testing-offramps">
    Customer sends tokens, receives fiat in their bank account.
  </Card>

  <Card title="Swap" icon="right-left" href="/guides/testing-swaps">
    Customer exchanges one token for another.
  </Card>
</CardGroup>

## Core concepts & reference

<CardGroup cols={2}>
  <Card title="Authentication" icon="key" href="/authentication">
    API-key auth, sandbox vs. production keys, and the one header gotcha.
  </Card>

  <Card title="Errors" icon="circle-exclamation" href="/errors">
    Every status code the API returns, with causes and fixes.
  </Card>

  <Card title="Pagination" icon="layer-group" href="/pagination">
    How to page through bank accounts and orders with date filters.
  </Card>

  <Card title="Idempotency" icon="rotate" href="/idempotency">
    Client-generated UUIDs make retries safe and prevent double orders.
  </Card>

  <Card title="Webhooks" icon="bell" href="/webhooks">
    Signed, real-time event delivery for orders, KYC, and bank accounts.
  </Card>

  <Card title="SDKs" icon="cube" href="/sdks">
    TypeScript and Rust libraries for the on-chain Stablebond side.
  </Card>
</CardGroup>

## Build with AI & tools

<CardGroup cols={3}>
  <Card title="MCP Server" icon="robot" href="/mcp-overview">
    Connect Claude, ChatGPT, or any MCP client and drive the Etherfuse API in natural language.
  </Card>

  <Card title="llms.txt" icon="file-lines" href="https://docs.etherfuse.com/llms.txt">
    A machine-readable index of these docs for LLMs and AI assistants.
  </Card>

  <Card title="OpenAPI spec" icon="file-code" href="https://api.etherfuse.com/openapi.json">
    Download `openapi.json` to import into Postman, Insomnia, or generate a client.
  </Card>
</CardGroup>