# OP Mainnet DEX Slippage & Price Impact Estimator

> OP Mainnet DEX Slippage & Price Impact Estimator is a paid API for AI agents from x402.donnyautomation.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Simulates a swap on Optimism (OP Mainnet) against live AMM reserves across SushiSwap and Uniswap v3 fee tiers to return the best execution venue, expected amount out, price impact in basis points, pool fee, and routing savings.

## Facts

- Endpoint: GET https://x402.donnyautomation.com/optimism/slippage
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/op-mainnet-dex-slippage-price-impact-estimator-b1b138cd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_esU0Bs0yzkcJeMQ0cpFU0

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 op-mainnet-dex-slippage-price-impact-estimator-b1b138cd
```

Example prompt: Before I execute my trade, check what slippage and price impact I'll actually get swapping WETH for USDC on Optimism — run it against SushiSwap and Uniswap v3 pools and tell me the best venue and exact amount out.

## When to prefer this

Use this endpoint when you need pre-trade execution simulation specifically on Optimism (OP Mainnet) and want to compare SushiSwap against multiple Uniswap v3 fee tiers simultaneously. Prefer it over generic spot price APIs when actual trade size matters and you need price impact in basis points, not just a reference price. It is ideal for trading bots, DEX aggregators, or smart order routing systems operating on Optimism that need to validate execution quality before submitting an on-chain transaction.

## Known failure modes

- Invalid or unsupported token pair symbol returns an error (e.g. unrecognized ticker)
- Token pair with no live liquidity on OP Mainnet returns empty or null execution data
- Network or RPC issues reading live OP Mainnet reserves may cause stale or failed responses
- Missing required 'pair' query parameter returns a 400 validation error
- Payment not completed (x402) results in a 402 Payment Required response before data is returned

## How this service works

What a trade size actually executes at on OP Mainnet, simulated against live reserves. Returns best (venue, amountOut, executionPrice, priceImpactBps, feeBps, totalCostBps), routingGain, venues[]. Requires ?pair=SYM/SYM AND ?amountUsd=25000 (or ?amountIn=). pair alone = 400 missing_amount. Errors: 400 bad_pair|missing_amount|bad_amount, 404 no_pools|no_quote|cannot_size_in_usd, 502 upstream_read_failed. Spot price without a size is /price. Chain-pinned; bare /slippage = BSC.

## Output

Returns the best execution venue (SushiSwap or Uniswap v3 fee tier), expected amount out for the trade, price impact expressed in basis points, the pool fee, and the savings achieved by optimal routing versus simply taking the best quoted spot price — all computed against live on-chain reserves on OP Mainnet.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "pair",
      "amountUsd"
     ],
     "properties": {
      "pair": {
       "type": "string",
       "description": "Token pair as SYM/SYM on OP Mainnet (e.g. WETH/USDC)."
      },
      "amountIn": {
       "type": "string",
       "description": "Trade size denominated in the FIRST pair symbol instead of USD. An alternative to amountUsd; supplying either one is enough."
      },
      "amountUsd": {
       "type": "string",
       "description": "Trade size in USD, e.g. 10000. Required unless amountIn is given instead."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ts": "2026-07-31T00:00:00.000Z",
  "chainId": 10,
  "network": "optimism"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/op-mainnet-dex-slippage-price-impact-estimator-b1b138cd/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.donnyautomation.com](https://www.zero.xyz/host/x402.donnyautomation.com/llms.txt)