API · x402

Resolve a DOI to publication metadata - citation text, identifiers and source links

by Saylor Innovations Knowledge Base · verified provider · updated 2026-10-26

What it does

Capabilities

verify a citation
resolve a DOI
collect publication metadata

Tags: research · doi · citations

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/doi-citation-report.json for the price and payment options.
Pay. Call GET https://saylorinnovations.com/api/research/doi?doi={doi}. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC or USDT or SOL on Base, Polygon, Arbitrum One, Solana, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.01 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base, Polygon, Arbitrum One, Solana

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.01	0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa	120s
exact	Polygon eip155:137	USDC	$0.01	0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa	120s
exact	Arbitrum One eip155:42161	USDC	$0.01	0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa	120s
exact	Solana solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	USDC	$0.01	7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7	120s
exact	Solana solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	USDT	$0.01	7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7	120s
exact	Solana solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	SOL	$0.01	7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7	120s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 120
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa",
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 120
  },
  {
    "scheme": "exact",
    "network": "eip155:42161",
    "payTo": "0xA2A8dF0f7CaaBEa4e120a2568118f141569fc8aa",
    "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 120
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 120
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
    "asset": "Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 120
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
    "asset": "So11111111111111111111111111111111111111112",
    "amount": "95830",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 120
  }
]

Schemas

Output schema (JSON Schema)

{
  "type": "object",
  "required": [
    "service",
    "subject",
    "retrievedAt",
    "source",
    "report"
  ],
  "properties": {
    "service": {
      "type": "string",
      "description": "Service name"
    },
    "subject": {
      "type": "string",
      "description": "What this response is for"
    },
    "retrievedAt": {
      "type": "string",
      "format": "date-time",
      "description": "Time the data was retrieved from the source (UTC)"
    },
    "source": {
      "type": "object",
      "required": [
        "name",
        "url"
      ],
      "properties": {
        "name": {
          "type": "string",
          "description": "Name"
        },
        "url": {
          "type": "string",
          "format": "uri",
          "description": "Canonical URL"
        }
      },
      "description": "Data source the values come from"
    },
    "report": {
      "type": "object",
      "required": [
        "doi",
        "title",
        "authors",
        "citation"
      ],
      "properties": {
        "doi": {
          "type": "string",
          "description": "Digital object identifier"
        },
        "title": {
          "type": "string",
          "description": "Title"
        },
        "authors": {
          "type": "array",
          "items": {
            "type": "string"
          },
          "description": "Author names"
        },
        "publisher": {
          "type": [
            "string",
            "null"
          ]
        },
        "publication": {
          "type": [
            "string",
            "null"
          ]
        },
        "year": {
          "type": [
            "integer",
            "null"
          ],
          "description": "Calendar year"
        },
        "citation": {
          "type": "string",
          "description": "Formatted citation"
        },
        "referenceCount": {
          "type": [
            "integer",
            "null"
          ],
          "description": "Number of reference"
        },
        "citedByCount": {
          "type": [
            "integer",
            "null"
          ],
          "description": "Number of cited by"
        },
        "type": {
          "type": [
            "string",
            "null"
          ],
          "description": "Type or kind"
        },
        "url": {
          "type": "string",
          "description": "Canonical URL"
        }
      },
      "description": "Structured report for the subject, with the fields described in the example"
    },
    "sample": {
      "type": [
        "boolean",
        "null"
      ],
      "description": "True when this is a fixed sample response"
    },
    "fixedSubject": {
      "type": [
        "string",
        "null"
      ],
      "description": "True when the sample is for a fixed subject"
    },
    "exampleTruncated": {
      "type": [
        "boolean",
        "null"
      ],
      "description": "True when the example is shortened"
    }
  }
}

Example shape — generated from the schema, not a captured live response

{
  "service": "string",
  "subject": "string",
  "retrievedAt": "2026-01-01T00:00:00Z",
  "source": {
    "name": "string",
    "url": "https://example.com"
  },
  "report": {
    "doi": "string",
    "title": "string",
    "authors": [
      "string"
    ],
    "publisher": "string",
    "publication": "string",
    "year": 0,
    "citation": "string",
    "referenceCount": 0,
    "citedByCount": 0,
    "type": "string",
    "url": "string"
  },
  "sample": true,
  "fixedSubject": "string",
  "exampleTruncated": true
}

Examples

curl

curl "https://saylorinnovations.com/api/research/doi?doi={doi}"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://saylorinnovations.com/api/research/doi?doi={doi}");
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://saylorinnovations.com/api/research/doi?doi={doi}")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: Saylor Innovations Knowledge Base
Endpoint: https://saylorinnovations.com/api/research/doi?doi={doi}
Side effects: Paid calls settle the advertised payment; see the provider contract for execution behavior.
Machine-readable: /resources/doi-citation-report.json