Gas Price Check

Get current Ethereum gas fees: safe, standard and fast prices in Gwei plus the base fee, from the priority fees paid over the last 20 blocks.

Pay by wallet (x402) gas-price-check

Example

Example answer

{
  "chain_id": "1",
  "base_fee_gwei": 0.111812277,
  "fast_gas_gwei": 0.122993504,
  "safe_gas_gwei": 0.111812277,
  "gas_used_ratio": "0.79543645,0.18742179029228,0.0750681879814453,0.97324925,0.586948583333333",
  "proposed_gas_gwei": 0.112812277
}

Inputs

Field	Type	Required	What it is
`chain_id`	string	No	Chain ID: 1 (Ethereum), 137 (Polygon PoS) or 56 (BNB Smart Chain). Rollups are refused. Default: 1

Output fields

How reliably each field appears in a successful answer.

Field	Type	Appears
`chain_id`	string	Always (present in every successful answer)
`base_fee_gwei`	number	Usually (present for most inputs)
`fast_gas_gwei`	number	Usually (present for most inputs)
`safe_gas_gwei`	number	Usually (present for most inputs)
`blocks_sampled`	number	Always (present in every successful answer)
`gas_used_ratio`	string	Usually (present for most inputs)
`proposed_gas_gwei`	number	Usually (present for most inputs)

How to call it

The same tool through each route. MCP clients reach it through Strale’s server at https://api.strale.io/mcp; the call below is what the agent sends.

# Needs an API key. max_price_cents caps what this call may cost.
curl -X POST https://api.strale.io/v1/do \
  -H "Authorization: Bearer $STRALE_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
    "capability_slug": "gas-price-check",
    "inputs": {},
    "max_price_cents": 2
  }'

{
  "tool": "strale_execute",
  "arguments": {
    "slug": "gas-price-check",
    "inputs": {},
    "max_price_cents": 2
  }
}

import { Strale } from "straleio";

const strale = new Strale({ apiKey: process.env.STRALE_API_KEY! });
const result = await strale.do({
  capability_slug: "gas-price-check",
  inputs: {},
  max_price_cents: 2,
});

import os
from straleio import Strale, DoRequest

strale = Strale(api_key=os.environ["STRALE_API_KEY"])
result = strale.do(DoRequest(
    capability_slug="gas-price-check",
    inputs={},
    max_price_cents=2,
))

# No account. The first request answers 402 with the price in USDC;
# an x402 client pays it from your wallet and repeats the request.
curl -i 'https://api.strale.io/x402/v2/gas-price-check?'

Limitations

Output reflects the requested chain's fee history (eth_feeHistory via Alchemy) at query time. Dependent on upstream API availability; may degrade if the provider rate-limits or is temporarily unavailable.
Chains covered
Ethereum (1), Polygon PoS (137) and BNB Smart Chain (56). Rollups such as Base, Arbitrum and OP Mainnet are refused: most of a transaction's cost there is the fee for posting its data to Ethereum, which fee history does not contain, so these tiers would understate it.
Fee tiers are computed, not quoted
Safe, proposed and fast are the next block's base fee plus the median priority fee paid at the 10th, 50th and 90th percentile over the last 20 blocks. They are estimates of what recent transactions paid, not a guarantee of inclusion.