Saylor Innovations Data Desk

Name: Saylor Innovations Data Desk
Price: 0.01 USDC
Availability: InStock

Function selector and event topic hash from a signature such as Transfer(address,address,uint256): 4-byte id and 32-byte keccak256, computed locally.

DataLiveeip155:8453Exactvia cdp

https://saylorinnovations.com/api/chain/signature-hash

Function selector from nameEvent topic hashKeccak256 signature4 byte selectorTopic0 calculator

Calls · 30d

This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 6 snapshots so far.

$15.76

Verified settled volume

1,657 settlements proven x402 by their on-chain EIP-3009 marker.

$0.010

Listed price

As published in the catalog. Always read the live 402 before paying.

Calls · 30d

Upstream's own call count for this endpoint, not ours.

Unique payers · 30d

Last called 2026-10-23 00:50Z

—

Upstream on-chain volume

Reported by the source catalog.

Paid to

0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa

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 to access this resource.",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "memo": "saylor:datadesk:chain-signature-",
        "name": "USD Coin",
        "note": "Base settles through an x402 facilitator. Send payload.signature and payload.authorization (EIP-3009); there is no self-submitted path on this network.",
        "version": "2",
        "facilitatorOnly": true,
        "assetTransferMethod": "eip3009"
      },
      "payTo": "0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa",
      "amount": "10000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
      "extra": {
        "memo": "saylor:datadesk:chain-signature-",
        "name": "USD Coin",
        "note": "Polygon settles through an x402 facilitator. Send payload.signature and payload.authorization (EIP-3009); there is no self-submitted path on this network.",
        "version": "2",
        "facilitatorOnly": true,
        "assetTransferMethod": "eip3009"
      },
      "payTo": "0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa",
      "amount": "10000",
      "scheme": "exact",
      "network": "eip155:137",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
      "extra": {
        "memo": "saylor:datadesk:chain-signature-",
        "name": "USD Coin",
        "note": "Arbitrum settles through an x402 facilitator. Send payload.signature and payload.authorization (EIP-3009); there is no self-submitted path on this network.",
        "version": "2",
        "facilitatorOnly": true,
        "assetTransferMethod": "eip3009"
      },
      "payTo": "0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa",
      "amount": "10000",
      "scheme": "exact",
      "network": "eip155:42161",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
      "extra": {
        "memo": "saylor:datadesk:chain-signature-",
        "session": "eyJhcnRpY2xlSWQiOiJkYXRhZGVzazpjaGFpbi1zaWduYXR1cmUtaGFzaCIsInJlZmVyZW5jZSI6IkY4ZndydExhMWpneFUxTVFLelVnenRDczUzaVRuRU1GVmRmdVg0eDZYajRaIiwicmVjaXBpZW50IjoiN0xTamZySmY4Zk5zQjhWQTl1N04zV0VuMjVzbVFMcG9iM1N2eVV2WGFjeTciLCJtaW50IjoiRVBqRldkZDVBdWZxU1NxZU0ycU4xeHp5YmFwQzhHNHdFR0drWnd5VER0MXYiLCJtaW5BbW91bnQiOjEwMDAwLCJleHAiOjE3OTI1NTgwNjEwNTN9.ickuaEogeh8FzCtPjYdJu7FOOMS-Ka6bahryXJLYEfQ",
        "feePayer": "BFK9TLC3edb13K6v4YyH3DwPb5DSUpkWvb7XnqCL9b4F",
        "reference": "F8fwrtLa1jgxU1MQKzUgztCs53iTnEMFVdfuX4x6Xj4Z"
      },
      "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
      "amount": "10000",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB",
      "extra": {
        "memo": "saylor:datadesk:chain-signature-",
        "session": "eyJhcnRpY2xlSWQiOiJkYXRhZGVzazpjaGFpbi1zaWduYXR1cmUtaGFzaCIsInJlZmVyZW5jZSI6IkdaR0dCRHk2aUV6cGJxaFE3QTNzSENwV3lwTjJqMzRyUVh4dURkU1hreFhNIiwicmVjaXBpZW50IjoiN0xTamZySmY4Zk5zQjhWQTl1N04zV0VuMjVzbVFMcG9iM1N2eVV2WGFjeTciLCJtaW50IjoiRXM5dk1GcnphQ0VSbUpmckY0SDJGWUQ0S0NvTmtZMTFNY0NlOEJlbndOWUIiLCJtaW5BbW91bnQiOjEwMDAwLCJleHAiOjE3OTI1NTgwNjEwNTN9.sCtoWAz5oLfKlaVaPd1cI80fScYZ2AshAg_t-l1cZMM",
        "feePayer": "BFK9TLC3edb13K6v4YyH3DwPb5DSUpkWvb7XnqCL9b4F",
        "reference": "GZGGBDy6iEzpbqhQ7A3sHCpWypN2j34rQXxuDdSXkxXM"
      },
      "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
      "amount": "10000",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "So11111111111111111111111111111111111111112",
      "extra": {
        "memo": "saylor:datadesk:chain-signature-",
        "note": "Native SOL: send lamports with a system transfer, not an SPL transfer. Price is quoted live and this quote expires in 120s.",
        "native": true,
        "session": "eyJhcnRpY2xlSWQiOiJkYXRhZGVzazpjaGFpbi1zaWduYXR1cmUtaGFzaCIsInJlZmVyZW5jZSI6IjN3bUppZVpoS1RYWUtEaXdVQ0pDRktFQUJRRUtrOFlic1ROVXBiTHhwTlhtIiwicmVjaXBpZW50IjoiN0xTamZySmY4Zk5zQjhWQTl1N04zV0VuMjVzbVFMcG9iM1N2eVV2WGFjeTciLCJtaW50IjpudWxsLCJtaW5BbW91bnQiOjkxODEyLCJleHAiOjE3OTI1NTgwNjEwNTN9.ylGp3wJ965bN9u-yL5BZe8XxvaqDCIiUhiKl-N-Lmbw",
        "reference": "3wmJieZhKTXYKDiwUCJCFKEABQEKk8YbsTNUpbLxpNXm",
        "solUsdPrice": 105.65,
        "quotedLamports": "94652"
      },
      "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
      "amount": "91812",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 120
    }
  ],
  "resource": {
    "url": "https://saylorinnovations.com/api/chain/signature-hash?signature=Transfer(address,address,uint256)",
    "tags": [
      "function selector from name",
      "event topic hash",
      "keccak256 signature",
      "4 byte selector",
      "topic0 calculator"
    ],
    "iconUrl": "https://saylorinnovations.com/og-image.jpg",
    "mimeType": "application/json",
    "description": "Function selector and event topic hash from a signature such as Transfer(address,address,uint256): 4-byte id and 32-byte keccak256, computed locally.",
    "serviceName": "Saylor Innovations Data Desk"
  },
  "extensions": {
    "tags": [
      "function selector from name",
      "event topic hash",
      "keccak256 signature",
      "4 byte selector",
      "topic0 calculator"
    ],
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "signature": "Transfer(address,address,uint256)"
          }
        },
        "output": {
          "type": "json",
          "example": {
            "note": "function_selector (and error_selector) are the first 4 bytes of the keccak256 hash of the signature; event_topic0 is the full 32-byte hash used as the first log topic.",
            "source": "Computed locally (keccak256)",
            "signature": "Transfer(address,address,uint256)",
            "event_topic0": "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
            "error_selector": "0xddf252ad",
            "known_function": null,
            "function_selector": "0xddf252ad"
          }
        }
      },
      "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": [
                  "signature"
                ],
                "properties": {
                  "signature": {
                    "type": "string",
                    "description": "a function, event or error signature with types only, for example Transfer(address,address,uint256)"
                  }
                }
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string",
                "const": "json"
              },
              "example": {
                "type": "object",
                "required": [
                  "signature",
                  "function_selector",
                  "event_topic0",
                  "note",
                  "source"
                ],
                "properties": {
                  "note": {
                    "type": "string",
                    "description": "plain-language reading of the result"
                  },
                  "source": {
                    "type": "string",
                    "description": "where the data was read from or how it was computed"
                  },
                  "signature": {
                    "type": "string",
                    "description": "the normalised signature hashed"
                  },
                  "event_topic0": {
                    "type": "string",
                    "description": "full 32-byte hash for event logs"
                  },
                  "error_selector": {
                    "type": "string",
                    "description": "first 4 bytes, used for custom errors"
                  },
                  "known_function": {
                    "type": [
                      "string",
                      "null"
                    ],
                    "description": "matching common function if any"
                  },
                  "function_selector": {
                    "type": "string",
                    "description": "first 4 bytes of the keccak256 hash"
                  }
                }
              }
            }
          }
        }
      }
    },
    "method": "GET",
    "example": {
      "note": "function_selector (and error_selector) are the first 4 bytes of the keccak256 hash of the signature; event_topic0 is the full 32-byte hash used as the first log topic.",
      "source": "Computed locally (keccak256)",
      "signature": "Transfer(address,address,uint256)",
      "event_topic0": "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
      "error_selector": "0xddf252ad",
      "known_function": null,
      "function_selector": "0xddf252ad"
    },
    "license": "LicenseRef-Saylor-Agent-Use-1.0",
    "mimeType": "application/json",
    "freshness": "fetched live (cached up to 1 hour for large reference files)",
    "tokenCount": null,
    "inputSchema": {
      "signature": "a function, event or error signature with types only, for example Transfer(address,address,uint256)"
    },
    "serviceName": "Saylor Innovations Data Desk",
    "instructions": "STANDARD PATH (works with stock x402 clients): send payload.transaction — a base64 partially-signed Solana transaction — and we route verify/settle through an x402 facilitator that sponsors the fee and submits it. Include the chosen accepts entry as \"accepted\" so we can match terms. ALTERNATIVE PATH (no facilitator): Pick ONE entry from accepts and use the reference and session from THAT entry — each asset has its own. USDC or USDT: send an SPL transfer of the exact amount. Native SOL (asset=So11111111111111111111111111111111111111112, extra.native=true): send that many lamports with a system transfer. Either way include extra.reference as a read-only account (Solana Pay style), then retry with PAYMENT-SIGNATURE: base64({x402Version:2, payload:{session, reference}}). If your client cannot attach a reference, send payload.signature instead (USDC only). SOL amounts are quoted live and expire in 120s; stablecoins do not move. The facilitator path verifies and settles in this request. Only the alternative self-submitted Solana path needs retries while the transfer is indexed (typically 3-4 attempts over 10-20s). On that path, a 402 saying \"payment not found on-chain yet\" means keep retrying.",
    "outputSchema": {
      "type": "object",
      "required": [
        "signature",
        "function_selector",
        "event_topic0",
        "note",
        "source"
      ],
      "properties": {
        "note": {
          "type": "string",
          "description": "plain-language reading of the result"
        },
        "source": {
          "type": "string",
          "description": "where the data was read from or how it was computed"
        },
        "signature": {
          "type": "string",
          "description": "the normalised signature hashed"
        },
        "event_topic0": {
          "type": "string",
          "description": "full 32-byte hash for event logs"
        },
        "error_selector": {
          "type": "string",
          "description": "first 4 bytes, used for custom errors"
        },
        "known_function": {
          "type": [
            "string",
            "null"
          ],
          "description": "matching common function if any"
        },
        "function_selector": {
          "type": "string",
          "description": "first 4 bytes of the keccak256 hash"
        }
      }
    },
    "noPathTemplate": true,
    "settlementModes": [
      "facilitator-transaction",
      "self-submitted-reference"
    ],
    "typicalLatencyMs": 700
  },
  "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.

0.01USDC≈ $0.01 USD

on Base · exact scheme

Pay 0.01 USDC on Base to 0xA2A8…fc8aa. The signed payment is good for 2 minutes.

Paid to: 0xA2A8…fc8aa
USD Coin contract: 0x8335…02913
Payment window: 2 minutes
As published: 10000 smallest units

10000units

on Polygon · exact scheme