Roundhouse

QuickBuild

Inspect a token or any address on Base mainnet: contract vs EOA (incl. EIP-7702 delegation), bytecode size, ERC-20 name/symbol/decimals/totalSupply (raw and formatted; bytes32 symbols handled), proxy implementation (EIP-1967, beacon, ZeppelinOS/FiatToken), whether it is a well-known Base token (guards against spoofed symbols), and optionally the balance of `holder`. Read live from public Base RPC; metadata cached 1 h. All params optional: defaults to USDC on Base. Invalid input = 400, never...

DataLiveeip155:8453Exactvia cdp
https://quickbuild.quynguyenbac.workers.dev/api/base/token
Baseerc20TokenCryptoOnchain
Calls · 30d
2
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 15 snapshots so far.
$0.18
Verified settled volume
26 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.
2
Calls · 30d
Upstream's own call count for this endpoint, not ours.
2
Unique payers · 30d
Last called 2026-10-24 16:08Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x751a4c3841bE287544C371B4EE09Bd3366AeA7cf

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.

Live 402 challenge

Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.

{
  "error": "Payment required",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x751a4c3841bE287544C371B4EE09Bd3366AeA7cf",
      "amount": "2000",
      "scheme": "exact",
      "network": "eip155:8453",
      "mimeType": "application/json",
      "resource": "https://quickbuild.quynguyenbac.workers.dev/api/base/token",
      "description": "Inspect a token or any address on Base mainnet: contract vs EOA (incl. EIP-7702 delegation), bytecode size, ERC-20 name/symbol/decimals/totalSupply (raw and formatted; bytes32 symbols handled), proxy implementation (EIP-1967, beacon, ZeppelinOS/FiatToken), whether it is a well-known Base token (guards against spoofed symbols), and optionally the balance of `holder`. Read live from public Base RPC; metadata cached 1 h. All params optional: defaults to USDC on Base. Invalid input = 400, never...",
      "outputSchema": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
          },
          "discoverable": true
        },
        "output": {
          "type": "json",
          "example": {
            "name": "USD Coin",
            "proxy": {
              "standard": "ZeppelinOS (e.g. Circle FiatTokenProxy)",
              "implementation": "0x2Ce6311ddAE708829bc0784C967b7d77D19FD779"
            },
            "symbol": "USDC",
            "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
            "chainId": 8453,
            "isErc20": true,
            "decimals": 6,
            "wellKnown": true,
            "isContract": true,
            "accountType": "contract",
            "totalSupply": {
              "raw": "4276257891842451",
              "formatted": "4276257891.842451"
            },
            "codeSizeBytes": 1852
          }
        }
      },
      "maxAmountRequired": "2000",
      "maxTimeoutSeconds": 300
    }
  ],
  "resource": {
    "url": "https://quickbuild.quynguyenbac.workers.dev/api/base/token",
    "tags": [
      "base",
      "erc20",
      "token",
      "crypto",
      "onchain"
    ],
    "mimeType": "application/json",
    "description": "Inspect a token or any address on Base mainnet: contract vs EOA (incl. EIP-7702 delegation), bytecode size, ERC-20 name/symbol/decimals/totalSupply (raw and formatted; bytes32 symbols handled), proxy implementation (EIP-1967, beacon, ZeppelinOS/FiatToken), whether it is a well-known Base token (guards against spoofed symbols), and optionally the balance of `holder`. Read live from public Base RPC; metadata cached 1 h. All params optional: defaults to USDC on Base. Invalid input = 400, never...",
    "serviceName": "QuickBuild"
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
          }
        },
        "output": {
          "type": "json",
          "example": {
            "name": "USD Coin",
            "proxy": {
              "standard": "ZeppelinOS (e.g. Circle FiatTokenProxy)",
              "implementation": "0x2Ce6311ddAE708829bc0784C967b7d77D19FD779"
            },
            "symbol": "USDC",
            "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
            "chainId": 8453,
            "isErc20": true,
            "decimals": 6,
            "wellKnown": true,
            "isContract": true,
            "accountType": "contract",
            "totalSupply": {
              "raw": "4276257891842451",
              "formatted": "4276257891.842451"
            },
            "codeSizeBytes": 1852
          }
        }
      },
      "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": {
                  "holder": {
                    "type": "string",
                    "description": "Optional address whose balance of this token to include."
                  },
                  "address": {
                    "type": "string",
                    "description": "Token / contract address on Base (0x + 40 hex). Optional: defaults to USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913."
                  }
                }
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string"
              },
              "example": {
                "type": "object",
                "properties": {
                  "name": {
                    "type": [
                      "string",
                      "null"
                    ]
                  },
                  "proxy": {
                    "type": [
                      "object",
                      "null"
                    ]
                  },
                  "holder": {
                    "type": "object"
                  },
                  "symbol": {
                    "type": [
                      "string",
                      "null"
                    ]
                  },
                  "address": {
                    "type": "string"
                  },
                  "isErc20": {
                    "type": "boolean"
                  },
                  "decimals": {
                    "type": [
                      "integer",
                      "null"
                    ]
                  },
                  "wellKnown": {
                    "type": "boolean"
                  },
                  "isContract": {
                    "type": "boolean"
                  },
                  "accountType": {
                    "type": "string"
                  },
                  "totalSupply": {
                    "type": [
                      "object",
                      "null"
                    ],
                    "properties": {
                      "raw": {
                        "type": "string"
                      },
                      "formatted": {
                        "type": [
                          "string",
                          "null"
                        ]
                      }
                    }
                  },
                  "codeSizeBytes": {
                    "type": "integer"
                  }
                }
              }
            }
          }
        }
      }
    }
  },
  "x402Version": 2
}

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 0x751a…eA7cf. The signed payment is good for 5 minutes.

Paid to
0x751a…eA7cf
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": "0x751a4c3841bE287544C371B4EE09Bd3366AeA7cf",
    "amount": "2000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "queryParams": {
          "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
        }
      },
      "output": {
        "type": "json",
        "example": {
          "name": "USD Coin",
          "proxy": {
            "standard": "ZeppelinOS (e.g. Circle FiatTokenProxy)",
            "implementation": "0x2Ce6311ddAE708829bc0784C967b7d77D19FD779"
          },
          "symbol": "USDC",
          "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
          "chainId": 8453,
          "isErc20": true,
          "decimals": 6,
          "wellKnown": true,
          "isContract": true,
          "accountType": "contract",
          "totalSupply": {
            "raw": "4276257891842451",
            "formatted": "4276257891.842451"
          },
          "codeSizeBytes": 1852
        }
      }
    },
    "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": {
                "holder": {
                  "type": "string",
                  "description": "Optional address whose balance of this token to include."
                },
                "address": {
                  "type": "string",
                  "description": "Token / contract address on Base (0x + 40 hex). Optional: defaults to USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913."
                }
              }
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string"
            },
            "example": {
              "type": "object",
              "properties": {
                "name": {
                  "type": [
                    "string",
                    "null"
                  ]
                },
                "proxy": {
                  "type": [
                    "object",
                    "null"
                  ]
                },
                "holder": {
                  "type": "object"
                },
                "symbol": {
                  "type": [
                    "string",
                    "null"
                  ]
                },
                "address": {
                  "type": "string"
                },
                "isErc20": {
                  "type": "boolean"
                },
                "decimals": {
                  "type": [
                    "integer",
                    "null"
                  ]
                },
                "wellKnown": {
                  "type": "boolean"
                },
                "isContract": {
                  "type": "boolean"
                },
                "accountType": {
                  "type": "string"
                },
                "totalSupply": {
                  "type": [
                    "object",
                    "null"
                  ],
                  "properties": {
                    "raw": {
                      "type": "string"
                    },
                    "formatted": {
                      "type": [
                        "string",
                        "null"
                      ]
                    }
                  }
                },
                "codeSizeBytes": {
                  "type": "integer"
                }
              }
            }
          }
        }
      }
    }
  }
}

Provenance

Seen in the source catalog
2026-10-24 16:08Z
Last indexed by Roundhouse
2026-10-26 17:20Z
Last enriched (probe, favicon, geo)
2026-10-21 15:46Z
x402 version
2
Max timeout
300s
Liveness probe
HTTP 402
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

This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 15 snapshots so far. 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 QuickBuild 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=QuickBuild'
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://quickbuild.quynguyenbac.workers.dev/api/base/token, 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.