Related & Recommended Papers (by Seed Paper or Topic)

{
  "type": "object",
  "anyOf": [
    {
      "required": [
        "id"
      ]
    },
    {
      "required": [
        "doi"
      ]
    },
    {
      "required": [
        "q"
      ]
    }
  ],
  "properties": {
    "q": {
      "type": "string",
      "description": "query (alternative to id â relevance search)"
    },
    "id": {
      "type": "string",
      "description": "paper arXiv id, DOI, or OpenAlex id"
    },
    "doi": {
      "type": "string",
      "description": "alias for id (DOI form)"
    },
    "maxItems": {
      "type": "string",
      "default": "15",
      "description": "1-50"
    }
  },
  "additionalProperties": false
}

{
  "type": "object",
  "properties": {
    "count": {
      "type": "number",
      "description": "Number of items in `items` for this call -- e.g. 15 (the default `maxItems`) for a seed-paper lookup, 5 for a topic query with an explicit `maxItems` of 5."
    },
    "items": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "doi": {
            "type": [
              "string",
              "null"
            ],
            "description": "DOI string when the paper has one (e.g. \"10.1109/cvpr.2016.90\"); observed null on OpenAlex-sourced items the vendor has no DOI on file for."
          },
          "url": {
            "type": "null",
            "description": "Always null; the paper's landing-page URL is not returned."
          },
          "type": {
            "type": "string",
            "description": "Constant \"related_paper\" on every item observed."
          },
          "year": {
            "type": "number",
            "description": "Publication year, present on every item observed."
          },
          "title": {
            "type": "string",
            "description": "The paper's title, present on every item observed."
          },
          "venue": {
            "type": [
              "string",
              "null"
            ],
            "description": "Journal or venue name when known; observed null on several items with none on file, including arXiv preprints and some OpenAlex items."
          },
          "pdfUrl": {
            "type": "null",
            "description": "Always null; a direct PDF URL is not returned."
          },
          "source": {
            "type": "string",
            "description": "Which backing catalog surfaced this item, e.g. \"openalex\" or \"arxiv\"."
          },
          "authors": {
            "type": "array",
            "items": {
              "type": "string"
            },
            "description": "Published author list, in the order returned by the source. In one observed entry the source folded institutional affiliation/address fragments into this array."
          },
          "sources": {
            "type": "array",
            "items": {
              "type": "string"
            },
            "description": "Present only for a topic query, not a seed-paper lookup -- which backing catalog(s) match this item for a topic search; a single-element array matching `source` on every item observed."
          },
          "abstract": {
            "type": "string",
            "description": "Full abstract text on every item observed."
          },
          "published": {
            "type": "string",
            "description": "Publication date. Format varies by source: bare date (e.g. \"2016-06-01\") on OpenAlex-sourced items, full ISO-8601 timestamp (e.g. \"2015-03-25T21:11:05Z\") on arXiv-sourced items."
          },
          "relatedBy": {
            "type": "string",
            "description": "How this item was matched: \"openalex\" for a seed-paper lookup, \"query\" for a topic query."
          },
          "citedByCount": {
            "type": [
              "number",
              "null"
            ],
            "description": "Citation count on OpenAlex-sourced items; observed null on every arXiv-sourced item (arXiv's own index does not track this)."
          },
          "citationCount": {
            "type": [
              "number",
              "null"
            ],
            "description": "Same value as `citedByCount` on every item observed; null wherever `citedByCount` is null."
          },
          "openAccessUrl": {
            "type": "null",
            "description": "Always null; an open-access copy URL is not returned."
          }
        },
        "additionalProperties": false
      }
    }
  },
  "description": "The related-papers result.",
  "additionalProperties": false
}