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

# SDKs & APIs

> Choose the Base SDK, API, CLI, or MCP integration that matches what you are building.

Use these references when you know which interface your application needs. Start with the SDKs & APIs overview to compare every surface, or jump directly to accounts, AI agents, local development, or chain RPC methods.

## Choose an Integration Surface

<CardGroup cols={2}>
  <Card title="SDKs & APIs Overview" icon="book" href="/sdks/overview">
    Compare the wallet and payments SDK, Base MCP, the Base Chain API, and command-line tooling.
  </Card>

  <Card title="Wallet and Payments SDK" icon="wallet" href="/sdks/base-account/overview">
    Add universal sign-in, passkey-backed accounts, and one-tap USDC payments to your app.
  </Card>

  <Card title="Base MCP" icon="robot" href="/agents/overview">
    Give AI assistants access to wallet actions, swaps, signatures, and x402 payments.
  </Card>

  <Card title="base-anvil CLI" icon="terminal" href="/sdks/base-anvil">
    Build and test Base-native contracts locally with Base's Foundry toolchain.
  </Card>
</CardGroup>

## Call the Chain

<CardGroup cols={2}>
  <Card title="Base RPC Overview" icon="network-wired" href="/base-chain/api-reference/rpc-overview">
    Choose between standard block data and 200 ms Flashblock preconfirmations.
  </Card>

  <Card title="Ethereum JSON-RPC" icon="code" href="/base-chain/api-reference/ethereum-json-rpc-api/eth_blockNumber">
    Read chain state, estimate gas, send transactions, query logs, and subscribe to events.
  </Card>

  <Card title="Flashblocks API" icon="bolt" href="/base-chain/api-reference/flashblocks-api/flashblocks-api-overview">
    Use preconfirmation-aware methods and streams for sub-second application feedback.
  </Card>

  <Card title="Debug API" icon="bug" href="/base-chain/api-reference/debug-api/debug_traceTransaction">
    Trace transactions and replay blocks when debugging contract execution.
  </Card>

  <Card title="Base Services Hub" icon="grid-2" href="/get-started/base-services-hub">
    Find RPC, data, security, and other service providers that support Base builders.
  </Card>
</CardGroup>