# Base DEX Swap Quote

> Base DEX Swap Quote is a paid API for AI agents from x402.agentindex.world, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-11).

Returns a best-price DEX swap quote on Base by comparing Uniswap v2, Uniswap v3, and Aerodrome via on-chain Multicall3, including amount received, optimal path, and price impact.

## Facts

- Endpoint: GET https://x402.agentindex.world/base/quote?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-dex-swap-quote-b10543ff
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fuOBAoBKOdoIfRjE8xWmC

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability base-dex-swap-quote-b10543ff
```

Example prompt: What's the best swap quote for converting 1000000 USDC (token 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) to WETH (token 0x4200000000000000000000000000000000000006) on Base — compare Uniswap v2, Uniswap v3, and Aerodrome and tell me how much I'd receive and the price impact?

## When to prefer this

Choose this endpoint when you need a real-time, on-chain best-price quote for a token swap on Base that compares multiple DEX venues (Uniswap v2, Uniswap v3, Aerodrome) in a single call. It is ideal for pre-trade analysis, slippage estimation, and routing decisions before submitting a transaction. Prefer it over generic price APIs when you need actual path routing and price impact data rather than just an oracle spot price.

## Known failure modes

- Invalid or unsupported token address returns an error or zero quote
- No liquidity path found between the two tokens across all three DEXes
- amount_in of zero or negative rejected by exclusiveMinimum constraint
- RPC or Multicall3 on-chain call failure causing a timeout or 500 error
- Token pair only exists on one DEX, limiting comparison accuracy

## How this service works

Slippage estimate, swap quote, and best DEX price on Base - compares Uniswap v2, Uniswap v3, and Aerodrome on-chain via Multicall3, returns amount received, chosen path, and price impact.

## Output

Returns the estimated amount of token_out received, the selected DEX and swap path that yields the best price, the price impact percentage, and a slippage estimate — all derived from on-chain data via Multicall3 aggregating Uniswap v2, Uniswap v3, and Aerodrome pools on Base.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "token_in": {
   "type": "string",
   "title": "Token In"
  },
  "amount_in": {
   "type": "integer",
   "title": "Amount In",
   "exclusiveMinimum": 0
  },
  "token_out": {
   "type": "string",
   "title": "Token Out"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-dex-swap-quote-b10543ff/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.agentindex.world](https://www.zero.xyz/host/x402.agentindex.world/llms.txt)