# AgentFeed Paper Lookup by DOI

> AgentFeed Paper Lookup by DOI is a paid API for AI agents from x402.ochinimus.app, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-15).

Retrieves bibliographic metadata for an academic paper by DOI, including title, year, authors, venue, citation count, open-access URL, and abstract from OpenAlex.

## Facts

- Endpoint: GET https://x402.ochinimus.app/api/paper/10.1038%2Fnature14539?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentfeed-paper-lookup-by-doi-3277f2e9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_57haoNRTvrFjMa-chSuef

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability agentfeed-paper-lookup-by-doi-3277f2e9
```

Example prompt: What are the title, authors, and abstract for the paper with DOI 10.1038/nature14539?

## When to prefer this

Use this endpoint when you have a specific DOI and need structured bibliographic metadata including abstract and open-access URL without scraping publisher sites. Prefer this over general web search when you need machine-readable citation data, open-access status, or author lists directly tied to a DOI. It is especially useful when building citation graphs, verifying paper existence, or enriching references in a document.

## Known failure modes

- DOI not found in OpenAlex — returns empty or error response
- Malformed DOI in path causes 400 or routing error
- Abstract not available — returned as null for papers where OpenAlex does not hold it
- Open-access URL missing if paper is paywalled or not indexed
- Rate limiting or payment failure causes 402 response

## How this service works

Paper by DOI: title, year, authors, venue, citation count, open-access URL and the abstract where OpenAlex holds it (CC0 data). Use when you need to answer: What is the paper behind this DOI? Send the slash of the DOI as %2F in the path.

## Output

A JSON object containing the DOI, title, publication year, authors list (with total author count), venue name, citation count, language, OpenAlex ID, open-access details (including URL if available), abstract text (when held by OpenAlex under CC0), data source, license, and a cache indicator.

## Request schema (JSON Schema)

```json
{
 "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"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "doi"
     ],
     "properties": {
      "doi": {
       "type": "string",
       "description": "a DOI such as 10.1038/nature14539, its slash sent as %2F in the path"
      }
     }
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "data": {
       "type": "object",
       "properties": {
        "doi": {
         "type": "string"
        },
        "type": {
         "type": "string"
        },
        "year": {
         "type": "number"
        },
        "title": {
         "type": "string"
        },
        "venue": {
         "type": "string"
        },
        "cached": {
         "type": "boolean"
        },
        "source": {
         "type": "string"
        },
        "authors": {
         "type": "array"
        },
        "license": {
         "type": "string"
        },
        "abstract": {},
        "cited_by": {
         "type": "number"
        },
        "language": {
         "type": "string"
        },
        "open_access": {
         "type": "object"
        },
        "openalex_id": {
         "type": "string"
        },
        "authors_total": {
         "type": "number"
        }
       }
      },
      "paid": {
       "type": "boolean"
      },
      "tool": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentfeed-paper-lookup-by-doi-3277f2e9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.ochinimus.app](https://www.zero.xyz/host/x402.ochinimus.app/llms.txt)