# x402node Gas Price Comparison API

> x402node Gas Price Comparison API is a paid API for AI agents from api.x402node.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Returns live gas prices across Base, Ethereum, Arbitrum, Optimism, Polygon, and BSC sorted cheapest-first so agents can pick the lowest-cost chain right now.

## Facts

- Endpoint: GET https://api.x402node.dev/chain/gas-compare
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402node-gas-price-comparison-api-7ad7d594
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_du208qfuq6IQ0uOBIn79o

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 x402node-gas-price-comparison-api-7ad7d594
```

Example prompt: Which blockchain has the cheapest gas fees right now out of Base, Ethereum, Arbitrum, Optimism, Polygon, and BSC — give me the full list sorted from cheapest to most expensive so I can decide where to execute my transaction.

## When to prefer this

Use this endpoint when an agent needs to dynamically route a transaction or operation to the cheapest available EVM chain at execution time. Unlike LLM knowledge which is static, this provides real-time gas data that changes block-by-block. Prefer this over manual chain selection or hardcoded defaults whenever minimizing transaction cost matters.

## Known failure modes

- RPC node unreachable for one or more chains — partial results or error returned
- Network congestion causing stale or delayed gas data
- Payment not accepted — 402 response if USDC payment header missing or insufficient
- Rate limiting if called too frequently without valid payment

## How this service works

Live gas price across Base, Ethereum, Arbitrum, Optimism, Polygon and BSC sorted cheapest first - lets agents pick the cheapest chain to execute an operation right now, real-time data that changes constantly and LLMs cannot know. gas comparison, cheapest chain, multi chain gas, gas prices, which chain cheapest, cross chain gas Accepts payment on Base or Solana — either network works.

## Output

A list of EVM chains (Base, Ethereum, Arbitrum, Optimism, Polygon, BSC) with their current gas prices, sorted ascending from cheapest to most expensive, reflecting live on-chain data at the moment of the call.

## Example request

```json
{}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402node-gas-price-comparison-api-7ad7d594/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.x402node.dev](https://www.zero.xyz/host/api.x402node.dev/llms.txt)