# x402 Gas Price Oracle — Multi-Chain Live Gas & Swap Cost

> x402 Gas Price Oracle — Multi-Chain Live Gas & Swap Cost is a paid API for AI agents from x402-services-production.up.railway.app, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Returns live gas prices and estimated USD swap costs across major EVM chains (Base, Ethereum, Arbitrum, Optimism, Polygon, BSC), optionally filtered by chain.

## Facts

- Endpoint: POST https://x402-services-production.up.railway.app/api/exec/gas
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-gas-price-oracle-multi-chain-live-gas-swap-cost-9e708ac1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nTsZ2NBhuaSwsBZkqNbYg

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-gas-price-oracle-multi-chain-live-gas-swap-cost-9e708ac1 -d '<json body>'
```

Example prompt: What are the live gas prices on Base, Ethereum, Arbitrum, and Optimism right now, and how much would a swap cost in USD on each?

## When to prefer this

Use this endpoint when an agent needs to compare real-time gas prices and swap costs across multiple EVM chains simultaneously to route a transaction or time execution for minimum cost. Prefer this over chain-specific RPC calls when multi-chain comparison is the goal.

## Known failure modes

- Unsupported chain identifier returns an error or is silently ignored
- Network congestion or RPC outage may cause stale or missing data for a specific chain
- Empty chains object may default to all chains or return an error depending on payload parsing
- Rate limiting if called too frequently without valid x402 payment

## How this service works

Live gas prices across major chains (Base, Ethereum, Arbitrum, Optimism, Polygon, BSC) with estimated USD cost of a swap. Send { chains? }. Time and route transactions for the cheapest execution.

## Output

Returns current gas prices (in gwei or native units) and estimated USD cost of a standard swap for each requested chain (or all supported chains by default: Base, Ethereum, Arbitrum, Optimism, Polygon, BSC), enabling cost-based routing decisions.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "chains": {
   "type": "object",
   "description": "Optional array of chains; defaults to all supported"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-gas-price-oracle-multi-chain-live-gas-swap-cost-9e708ac1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-services-production.up.railway.app](https://www.zero.xyz/host/x402-services-production.up.railway.app/llms.txt)