# Research Paper Profile by DOI

> Research Paper Profile by DOI is a paid API for AI agents from research-papers.x402tookit.com, paid per call via x402, $0.03/call, status unknown (last checked 2026-10-31).

Returns a comprehensive profile for a research paper identified by DOI, including title, journal, year, citation count, field-weighted impact, open-access link, and retraction status.

## Facts

- Endpoint: GET https://research-papers.x402tookit.com/paper-lookup?utm_source=zero.xyz
- Price: $0.03/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/research-paper-profile-by-doi-d2cd0d24
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sHE7ieSfbRAC2g0xyuLBc

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 research-paper-profile-by-doi-d2cd0d24
```

Example prompt: Can you pull up the full profile for the paper with DOI 10.1038/s41586-021-03819-2 — I want to know the title, journal, citation count, field-weighted impact score, whether it's open access, and if it's been retracted?

## When to prefer this

Use this endpoint when you have a specific DOI and need a comprehensive single-paper profile covering bibliometrics, impact, open access, and retraction status in one call. Prefer this over separate citation or retraction endpoints when you need multiple data points about one paper simultaneously. Choose this over a topic-search endpoint when you already know the exact DOI.

## Known failure modes

- DOI not found in OpenAlex or Crossref — returns null fields or degraded response
- Malformed or non-existent DOI — may return empty or error response
- Retraction data unavailable for some papers — retractionStatus may be null
- Field-weighted impact not computable for very new or obscure papers
- Open-access link missing even when paper exists — openAccess.isOpen may be false or null
- Service degraded flag set when one data source is unavailable

## How this service works

Paper profile by DOI: title, journal, year, citations, field-weighted impact, open-access link and retraction state.

## Output

Returns a structured paper profile including: DOI, title, journal name, publisher, publication year, number of authors, first author, cited-by count, references count, field-weighted citation impact score, open-access status and URL, retraction status, topic/field, a brief summary, a quality verdict with reasons, and any checks that were skipped.

## 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"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "doi"
     ],
     "properties": {
      "doi": {
       "type": "string",
       "description": "DOI of the paper"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "doi": {
       "type": [
        "null",
        "string"
       ]
      },
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "type": {
       "type": [
        "null",
        "string"
       ]
      },
      "year": {
       "type": [
        "null",
        "number"
       ]
      },
      "title": {
       "type": [
        "null",
        "string"
       ]
      },
      "topic": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "authors": {
       "type": [
        "null",
        "number"
       ]
      },
      "journal": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "publisher": {
       "type": [
        "null",
        "string"
       ]
      },
      "sourceUrl": {
       "type": [
        "null",
        "string"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "openAccess": {
       "type": [
        "null",
        "object"
       ],
       "properties": {
   
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/research-paper-profile-by-doi-d2cd0d24/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from research-papers.x402tookit.com](https://www.zero.xyz/host/research-papers.x402tookit.com/llms.txt)