# Compass Settlement Cost Comparator

> Compass Settlement Cost Comparator is a paid API for AI agents from api.402rates.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Returns the simulated on-chain cost of a USDC transfer across up to five EVM chains (Base, Polygon, Arbitrum, Ethereum, XDC), ranked cheapest first using live gas prices and rollup L1 data fees.

## Facts

- Endpoint: GET https://api.402rates.com/v1/settlement/costs
- 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/compass-settlement-cost-comparator-066edbe3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kjRUFSXzRi9yCaelFreDK

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 compass-settlement-cost-comparator-066edbe3
```

Example prompt: Which blockchain is the cheapest to send USDC on right now — compare Base, Polygon, Arbitrum, Ethereum, and XDC and show me the gas costs ranked cheapest first.

## When to prefer this

Use this endpoint when you need a real-time, cross-chain comparison of USDC transfer costs using live gas prices and actual rollup L1 data fees rather than static estimates. It is the right choice when routing a USDC payment optimally, benchmarking settlement costs programmatically, or building a fee dashboard that reflects current on-chain conditions across Base, Polygon, Arbitrum, Ethereum, and XDC. Prefer it over manual gas tracker lookups because it returns a unified, pre-ranked response accounting for rollup overhead in a single call.

## Known failure modes

- Chain RPC unavailable — live gas price or block head cannot be fetched for one or more chains, causing partial or failed response
- Invalid 'chains' query parameter — value does not match the allowed comma-separated enum pattern, returns a 400 validation error
- Payment failure — x402 micropayment not settled, request blocked before execution
- Network timeout — on-chain simulation takes too long under congestion
- All chains congested — costs may spike and not reflect typical fees

## How this service works

What a USDC transfer actually costs on Base, Polygon, Arbitrum, Ethereum and XDC, measured rather than assumed: gas units simulated per chain against live prices and fresh chain heads, plus the rollup L1 data fee where it applies. Every figure ships with its inputs and the block it was read at, so you can recompute it. Cheapest first; a chain that cannot be measured is excluded, never estimated.

## Output

A list of chains sorted cheapest-first, each entry showing the simulated gas units consumed, the live gas price at the current block head, the rollup L1 data fee (where applicable), and the total computed cost in USDC for a standard USDC transfer.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "chains": {
       "type": "string",
       "pattern": "^(base|polygon|arbitrum|ethereum|xdc)(,(base|polygon|arbitrum|ethereum|xdc))*$",
       "description": "comma-separated list of: base, polygon, arbitrum, ethereum, xdc. Order does not matter and duplicates are ignored. Omit it to price all five, which is the usual call and costs exactly the same."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/compass-settlement-cost-comparator-066edbe3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.402rates.com](https://www.zero.xyz/host/api.402rates.com/llms.txt)