# x402node Mempool Gas Price Estimator

> x402node Mempool Gas Price Estimator is a paid API for AI agents from api.x402node.dev, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-02).

Returns real-time EVM gas price estimates (slow, standard, fast tiers in gwei) derived from the pending block base fee

## Facts

- Endpoint: GET https://api.x402node.dev/chain/mempool-gas?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402node-mempool-gas-price-estimator-da941ddd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_uq9BE6SxqlMWMOwJCOqhN

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-mempool-gas-price-estimator-da941ddd
```

Example prompt: What are the current gas prices on Ethereum right now — give me the slow, standard, and fast tier estimates in gwei so I know what to set for my transaction?

## When to prefer this

Use this endpoint when you need real-time, tiered gas price recommendations (slow/standard/fast) for EVM transactions and want estimates rooted in the actual pending block base fee rather than historical averages. Prefer it over static or cached gas APIs when transaction timing and cost accuracy matter, especially for DeFi operations, NFT mints, or any time-sensitive on-chain action.

## Known failure modes

- Unsupported or invalid chain ID returns an error or empty response
- Mempool data temporarily unavailable due to node connectivity issues
- Rate limit exceeded if called too frequently without payment
- Payment not processed correctly results in 402 response
- Chain currently has no pending block data available

## How this service works

Real-time gas estimates from the pending block base fee with slow/standard/fast tiers in gwei on EVM chains. mempool gas, pending gas, gas estimate, current gas price, fast gas, transaction fee Accepts payment on Base or Solana — either network works.

## Output

Returns three gas price tiers (slow, standard, fast) in gwei derived from the current pending block base fee, enabling the caller to choose an appropriate gas price for desired transaction confirmation speed on a given EVM chain.

## Example request

```json
{
 "chain": "ethereum"
}
```

## 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": {
      "chain": {
       "type": "string",
       "description": "ethereum (default), base, arbitrum, optimism, polygon"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402node-mempool-gas-price-estimator-da941ddd/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)