Roundhouse

gapfill

Current gas on Base: next block's base fee, low/medium/high priority fees from the last 20 blocks, gas price, ready-to-sign maxFeePerGas and maxPriorityFeePerGas, and the cost in ETH and USD of a transaction of any gas limit plus an ETH transfer, ERC-20 transfer and swap, including Base's L1 data fee. ETH/USD from Chainlink. For setting fees and budgeting transactions on Base.

TradingUnknowneip155:8453Exactvia cdp
https://jotowl.com/v1/base/gas
BaseGasFeeseip-1559L2
Settlements · 30d
17
No per-endpoint history for this service yet, so this is payments indexed to its PROVIDER's wallet over 30 days.
$0.07
Verified settled volume
17 settlements proven x402 by their on-chain EIP-3009 marker.
$0.0020
Listed price
As published in the catalog. Always read the live 402 before paying.
1
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-10-26 10:38Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x91A71892231A256d69d4bf8a442234701a762AaF

The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.

Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

Provider

The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.

Accepts

The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.

0.002USDC≈ $0.002 USD
on Base · exact scheme

Pay 0.002 USDC on Base to 0x91A7…62AaF. The signed payment is good for 5 minutes.

Paid to
0x91A7…62AaF
USD Coin contract
0x8335…02913
Payment window
5 minutes
As published
2000 smallest units
The catalog’s raw entry
[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "version": "2"
    },
    "payTo": "0x91A71892231A256d69d4bf8a442234701a762AaF",
    "amount": "2000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "queryParams": {
          "gasLimit": 21000
        }
      },
      "output": {
        "type": "json",
        "example": {
          "l1": {
            "note": "Base is an OP-stack L2: besides gas, each transaction pays an L1 data fee for its bytes. The fees here are GasPriceOracle.getL1FeeUpperBound for the unsigned size given (an upper bound; compressible calldata pays less).",
            "baseFeeScalar": 2269,
            "l1BaseFeeGwei": "0.089065968",
            "blobBaseFeeGwei": "0.005143647",
            "blobBaseFeeScalar": 1055762
          },
          "ethUsd": {
            "price": 2298.5718,
            "source": "Chainlink ETH/USD on Base",
            "updatedAt": "2026-10-26T03:50:09.000Z"
          },
          "method": "Priority fees are the medians, over the last 20 blocks, of each block's 10th, 50th and 90th percentile tips (eth_feeHistory). maxFeePerGas is twice the next base fee plus the tip. Costs use the next base fee plus the medium tip.",
          "source": "Base mainnet over public JSON-RPC (eth_feeHistory, eth_gasPrice, GasPriceOracle); ETH/USD from Chainlink on Base",
          "chainId": 8453,
          "gasPrice": "0.006",
          "congestion": {
            "blocks": 20,
            "baseFeeChangePct": 0,
            "averageGasUsedRatio": 0.1329
          },
          "blockNumber": 53098658,
          "baseFeePerGas": "0.005",
          "suggestedFees": {
            "low": {
              "maxFeePerGas": "10000370",
              "maxPriorityFeePerGas": "370"
            },
            "high": {
              "maxFeePerGas": "20625000",
              "maxPriorityFeePerGas": "10625000"
            },
            "unit": "wei",
            "medium": {
              "maxFeePerGas": "11000000",
              "maxPriorityFeePerGas": "1000000"
            }
          },
          "priorityFeePerGas": {
            "low": "0.00000037",
            "high": "0.010625",
            "node": "0.001",
            "medium": "0.001"
          },
          "commonTransactions": [
            {
              "eth": "0.000000126866391794",
              "usd": "0.0002916",
              "gwei": "126.866391794",
              "name": "ETH transfer",
              "txBytes": 55,
              "gasLimit": 21000,
              "executionEth": "0.000000126",
              "l1DataFeeEth": "0.000000000866391794",
              "operatorFeeEth": "0"
            },
            {
              "eth": "0.000000391145741634",
              "usd": "0.0008991",
              "gwei": "391.145741634",
              "name": "ERC-20 transfer",
              "txBytes": 125,
              "gasLimit": 65000,
              "executionEth": "0.00000039",
              "l1DataFeeEth": "0.000000001145741634",
              "operatorFeeEth": "0"
            },
            {
              "eth": "0.000000903146015026",
              "usd": "0.002076",
              "gwei": "903.146015026",
              "name": "DEX swap",
              "txBytes": 400,
              "gasLimit": 150000,
              "executionEth": "0.0000009",
              "l1DataFeeEth": "0.000000003146015026",
              "operatorFeeEth": "0"
            }
          ],
          "estimatedTransferCost": {
            "eth": "0.000000126866391794",
            "usd": "0.0002916",
            "gwei": "126.866391794",
            "txBytes": 55,
            "gasLimit": 21000,
            "executionEth": "0.000000126",
            "l1DataFeeEth": "0.000000000866391794",
            "operatorFeeEth": "0"
          }
        }
      }
    },
    "schema": {
      "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",
              "required": [],
              "properties": {
                "chain": {
                  "enum": [
                    "base"
                  ],
                  "type": "string",
                  "description": "Base only (the default)"
                },
                "txBytes": {
                  "type": "integer",
                  "maximum": 131072,
                  "minimum": 0,
                  "description": "The unsigned transaction's size, for its L1 data fee (default 55 for 21000 gas, else 125)"
                },
                "gasLimit": {
                  "type": "integer",
                  "default": 21000,
                  "maximum": 30000000,
                  "minimum": 21000,
                  "description": "Gas units to price: 21000 ETH transfer (default), 65000 ERC-20, 150000 swap"
                }
              }
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string"
            },
            "example": {
              "type": "object",
              "required": [
                "chainId",
                "blockNumber",
                "baseFeePerGas",
                "gasPrice",
                "priorityFeePerGas",
                "suggestedFees",
                "estimatedTransferCost",
                "commonTransactions"
              ],
              "properties": {
                "l1": {
                  "type": "object"
                },
                "ethUsd": {
                  "type": [
                    "object",
                    "null"
                  ],
                  "description": "price, source, updatedAt"
                },
                "chainId": {
                  "type": "integer",
                  "const": 8453
                },
                "gasPrice": {
                  "type": "string",
                  "description": "eth_gasPrice, gwei"
                },
                "congestion": {
                  "type": "object"
                },
                "blockNumber": {
                  "type": "integer"
                },
                "baseFeePerGas": {
                  "type": "string",
                  "description": "The next block's base fee, gwei"
                },
                "suggestedFees": {
                  "type": "object",
                  "description": "maxFeePerGas and maxPriorityFeePerGas per tier, wei"
                },
                "priorityFeePerGas": {
                  "type": "object",
                  "description": "low, medium, high (and the node's own suggestion), gwei"
                },
                "commonTransactions": {
                  "type": "array",
                  "items": {
                    "type": "object"
                  }
                },
                "estimatedTransferCost": {
                  "type": "object",
                  "description": "gasLimit, txBytes, total cost in gwei, eth and usd, with execution, L1 data and operator fees"
                }
              }
            }
          }
        }
      }
    }
  }
}

Provenance

Seen in the source catalog
2026-10-26 10:38Z
Last indexed by Roundhouse
2026-10-26 22:40Z
Last enriched (probe, favicon, geo)
—
x402 version
2
Max timeout
300s
Liveness probe
Not probed
Report

Hand this page to an agent

Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.

GET api.roundhouseai.io/v0/endpoints

No per-endpoint history for this service yet, so this is payments indexed to its PROVIDER's wallet over 30 days. Verified volume counts only settlements with an on-chain EIP-3009 marker.

Open skill.md
Show the prompt
Using Roundhouse, look up the x402 service gapfill and tell me whether it is
worth paying: what a call costs, whether the endpoint answered when last probed, and what
its payment record actually shows.

curl -s 'https://api.roundhouseai.io/v0/endpoints?q=gapfill'
curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>'

Then call it: read the price from the live 402 at https://jotowl.com/v1/base/gas, never from
a cached figure, and pay with an x402 client.

The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except
/v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at
GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at
https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further.

If you do not have Roundhouse tools or skills installed, read
https://roundhouseai.io/skill.md first — it is the whole procedure.