Saylor Innovations Agent Bazaar by Saylor Innovations
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mirrored listing x402 eip155:8453

Simulate a transaction before signing: runs `eth_estimateGas` for `{ to, from?, data?, val

Simulate a transaction before signing: runs `eth_estimateGas` for `{ to, from?, data?, value? }` and returns the estimated gas units and estimated fee (current gas price x gas, in wei + ETH). If the node rejects the call it returns `ok:false` with the decoded `revertReason` (why it would fail) instead of erroring. Reads live on-chain state with automatic endpoint fallback.

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Claim this listing
4000 (raw units)
price
1
calls / 30d
1
unique payers
2026-09-13
updated

Provider

chain.openverbs.com · discovered, not yet claimed by its owner

Payment (x402 accepts[])

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xb3f4de103F34b99f0Da19B4F16D6B53a14C2194A",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "4000",
    "maxTimeoutSeconds": 300
  }
]

Output schema

{
  "bazaar": {
    "info": {
      "input": {
        "body": {},
        "bodyType": "json",
        "method": "POST",
        "type": "http"
      }
    },
    "schema": {
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "properties": {
        "input": {
          "additionalProperties": false,
          "properties": {
            "body": {
              "additionalProperties": false,
              "properties": {
                "chain": {
                  "description": "EVM chain to query. One of: ethereum, base, arbitrum, optimism, polygon. Default \"ethereum\".",
                  "enum": [
                    "ethereum",
                    "base",
                    "arbitrum",
                    "optimism",
                    "polygon"
                  ],
                  "type": "string"
                },
                "data": {
                  "description": "Calldata hex (optional; e.g. an ERC-20 transfer).",
                  "pattern": "^0x([0-9a-fA-F]{2})*$",
                  "type": "string"
                },
                "from": {
                  "description": "Sender address (optional; affects state-dependent estimates).",
                  "pattern": "^0x[0-9a-fA-F]{40}$",
                  "type": "string"
                },
                "to": {
                  "description": "Destination address (contract or wallet).",
                  "pattern": "^0x[0-9a-fA-F]{40}$",
                  "type": "string"
                },
                "value": {
                  "description": "Native value in wei, decimal or 0x-hex (optional).",
                  "type": "string"
                }
              },
              "type": "object"
            },
            "bodyType": {
              "enum": [
                "json",
                "form-data",
                "text"
              ],
              "type": "string"
            },
            "method": {
              "enum": [
                "POST"
              ],
              "type": "string"
            },
            "type": {
              "const": "http",
              "type": "string"
            }
          },
          "required": [
            "type",
            "method",
            "bodyType",
            "body"
          ],
          "type": "object"
        }
      },
      "required": [
        "input"
      ],
      "type": "object"
    }
  }
}

Use it

curl

curl "https://chain.openverbs.com/v1/gas-estimate"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://chain.openverbs.com/v1/gas-estimate");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://chain.openverbs.com/v1/gas-estimate")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Machine-readable

Everything on this page is also available as clean JSON at /resources/12604.json, and this resource appears in /discovery/resources and /discovery/search.