# Silverback Base Chain Swap Quote

> Silverback Base Chain Swap Quote is a paid API for AI agents from silverback-x402.onrender.com, paid per call via x402, $0.01/call, status down (last checked 2026-09-15).

Returns the optimal EVM swap route on Base chain for a given token pair and input amount using 0x protocol

## Facts

- Endpoint: GET https://silverback-x402.onrender.com/api/v1/swap-quote
- Price: $0.01/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/silverback-x402-onrender-com-75c498bc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jEk8oUZ0fWOTyqGWjHUZp

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 silverback-x402-onrender-com-75c498bc
```

Example prompt: What's the best swap route on Base for trading 1.5 USDC into WETH right now — what's the optimal path and how much WETH would I get back?

## When to prefer this

Use this endpoint when you need an optimal swap quote specifically on Base chain (EVM) for ERC-20 tokens. It is distinct from Jupiter-based Solana quotes and is ideal for pre-trade analysis, price checking, or building swap UIs on Base. Prefer this over generic price feeds when you need routing and path optimization, not just a spot price.

## Known failure modes

- Token address not found or invalid — returns error if tokenIn/tokenOut are unrecognized
- Insufficient liquidity for the pair — no route found
- Amount too small or too large for available liquidity
- Invalid token format (non-EVM address used for Solana token — use /api/v1/jupiter-quote instead)
- Payment failure — $0.01 USDC x402 payment required per call
- Network timeout from Base chain RPC or 0x API

## How this service works

Get optimal swap route on Base chain (EVM only — for Solana tokens use /api/v1/jupiter-quote)

## Output

Returns the optimal swap route on Base chain including expected output token amount, price impact, routing path through DEX liquidity pools, and gas cost estimates for a given input token, output token, and input amount.

## Example request

```json
{
 "tokenIn": "USDC",
 "amountIn": "1.5",
 "tokenOut": "WETH"
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "tokenIn": {
   "type": "string",
   "description": "Input token address (0x format) or symbol (WETH, USDC)"
  },
  "amountIn": {
   "type": "string",
   "description": "Amount to swap (human readable, e.g. '1.5')"
  },
  "tokenOut": {
   "type": "string",
   "description": "Output token address (0x format) or symbol"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/silverback-x402-onrender-com-75c498bc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from silverback-x402.onrender.com](https://www.zero.xyz/host/silverback-x402.onrender.com/llms.txt)