# SilverbackDeFi Token Swap via 0x Permit2

> SilverbackDeFi Token Swap via 0x Permit2 is a paid API for AI agents from x402.silverbackdefi.app, paid per call via x402, $0.05/call, status down (last checked 2026-09-15).

Returns step-by-step EIP-712 signing instructions and code examples to execute a token swap on-chain using 0x Permit2

## Facts

- Endpoint: GET https://x402.silverbackdefi.app/api/v1/swap
- Price: $0.05/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-silverbackdefi-app-710d4cb0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FckTamm-p5DhY8bPqrPAb

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 x402-silverbackdefi-app-710d4cb0
```

Example prompt: I want to swap 0.5 WETH for USDC using my wallet 0xAbc123... — give me the EIP-712 signing instructions and transaction steps with 1% max slippage.

## When to prefer this

Use this endpoint when you need to execute a token swap on-chain via 0x Permit2 with EIP-712 signing, especially when you want code examples and step-by-step guidance for the signing and broadcast flow. Prefer this over generic DEX endpoints when you need structured signing instructions rather than just a quote.

## Known failure modes

- Invalid token symbol or address returns error with no swap data
- Unsupported token pair not available on 0x returns empty or error response
- Slippage too low causes quote to fail due to price movement
- Invalid wallet address format returns validation error
- Insufficient liquidity for requested amount returns no route found

## How this service works

Token swap via 0x Permit2. You sign EIP-712 data, append signature to tx, and broadcast. Response includes step-by-step instructions with code examples.

## Output

Returns structured step-by-step instructions including EIP-712 data to sign, how to append the signature to the transaction, and code examples for broadcasting the swap transaction on-chain via 0x Permit2.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "tokenIn": {
   "type": "string",
   "description": "Token to sell (symbol like USDC, WETH, VIRTUAL or 0x address)"
  },
  "amountIn": {
   "type": "string",
   "description": "Amount to swap in human-readable units (e.g. '0.1' for 0.1 WETH)"
  },
  "slippage": {
   "type": "string",
   "description": "Max slippage % (default: '1')"
  },
  "tokenOut": {
   "type": "string",
   "description": "Token to buy (symbol or 0x address)"
  },
  "walletAddress": {
   "type": "string",
   "description": "Your wallet address — you will sign the Permit2 data and submit the transaction"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-silverbackdefi-app-710d4cb0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.silverbackdefi.app](https://www.zero.xyz/host/x402.silverbackdefi.app/llms.txt)