Endpoint Playground

Try the Retrieve paper citation graphs API

Return one-hop Europe PMC citation edges, canonical seed IDs, source provenance and a frozen owner-bound cursor. Modes are references and citers; intent is unsupported. Partial results explicitly report indexed-source and candidate-window limits.

What a live request returned

14 Oct 2026: 1 items; 2 fields had a value in every checked item.

Observed request: POST /research/papers/related
Fields with a value in every checked item: paper, rank

Request: POST /research/papers/related
Cost: 3 credits/seed · up to 30
Auth: apiKey

Retrieve paper citation graphs API documentation Pricing

Prefilled cURL

curl 'https://api.crawlora.net/api/v1/research/papers/related' \
  -H "x-api-key: $CRAWLORA_API_KEY" \
  -X POST \
  --data '{}'

Request parameters

Parameter	Type	Required	Prefilled value	Description
request (body)	object	Yes		Seed IDs and graph direction, or cursor and optional limit

Example JSON response

{
  "code": 200,
  "msg": "OK",
  "data": {
    "seeds": [
      {
        "paper_id": "paper:seed-uuid",
        "primary_id": "europepmc:MED:17299597",
        "status": "ok"
      }
    ],
    "items": [
      {
        "paper": {
          "paper_id": "paper:neighbor-uuid",
          "primary_id": "europepmc:MED:10781045"
        },
        "rank": 1
      }
    ],
    "relations": [
      {
        "from_id": "paper:seed-uuid",
        "to_id": "paper:neighbor-uuid",
        "source_id": "europepmc",
        "source_url": "https://www.ebi.ac.uk/europepmc/webservices/rest/MED/17299597/references?format=json&page=1&pageSize=50",
        "retrieved_at": "2026-10-10T02:00:00Z"
      }
    ],
    "has_more": true,
    "next_cursor": "signed-owner-bound-cursor",
    "partial": false,
    "coverage": [
      {
        "source_id": "europepmc",
        "status": "ok"
      }
    ],
    "warnings": [],
    "usage": {
      "credits_charged": 3,
      "settlement_pending": false
    }
  }
}

More Research endpoints

Inspect paper metadata Read a research paper Search research papers List paper sources

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Endpoint

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1 shown

Group

Method

Auth

Endpoint

POSTapiKey3 credits/seed · up to 30Research

POST /research/papers/related

Get paper references or citing papers

Response behavior

`seeds` maps canonical seed IDs to primary source identifiers, with `status` exactly `ok` or `failed` for the validated list outcome. `items` contains normalized paper nodes. `relations` contains directed `from_id`/`to_id`, `source_id`, exact graph `source_url` and retrieval timestamp. An initial request captures up to 50 indexed neighbors per successful unique seed, with a combined 200-node window. Alias-equivalent seeds are queried/charged once. Shared neighbors retain edges from every successful seed. Each frozen page includes its nodes' seed relations. Source counts, unresolved/non-supported reference rows, deadline and candidate caps can make `partial=true`; warnings state the limitation. Citation lists can differ from the full bibliography and commercial citation databases. Snapshots last 30 minutes. Signed cursors bind owner, operation, normalized query and source revision. Continuation performs no source queries, returns zero new usage/cost, and retains the original coverage/provenance. Invalid/cross-owner cursors fail; expired or removed snapshots return `410`. Billing: 3 credits per successful unique seed whose metadata and graph response were validated and whose graph edges were retained, including genuine zero-neighbor responses. Positive lists that produce no retainable edges are not charged. Metadata resolution is included in this price; failed seed lookups are not charged. Initial static ceiling is 30 credits; dynamic precheck bounds the submitted seed count. Cursor pages cost zero. A partial response charges only successful delivered seed work. All-failed source work returns `503` with no charge; malformed inputs return `400`. Response enum values: - `paper.identifiers[].namespace`: `arxiv`, `doi`, `pmid`, `pmcid`. - `paper.content_level`: `metadata`, `abstract`, `full_text`. - `unavailable_reason`: `not_indexed`, `restricted`, `unsupported_format`, `not_found`. - `coverage[].status`: `ok`, `failed`, `not_indexed`, `unsupported`. - `coverage[].failure.reason`: `invalid_url`, `unsupported_content_type`, `blocked`, `not_found`, `rate_limited`, `timeout`, `upstream_error`, `internal_error`, `out_of_scope`, `robots_disallowed`, `duplicate`, `limit_reached`, `unsupported_filter`, `unknown_source`, `idempotency_conflict`, `invalid_cursor`, `result_expired`, `full_text_unavailable`, `budget_exhausted`. - `warnings[].code`: `source_failed`, `source_not_indexed`, `discovery_truncated`, `ranking_window_limit`, `imprecise_date_excluded`, `content_unavailable`, `cached_source_stale`. Example request: ```json {"seed_ids":["pmid:17299597"],"mode":"references","limit":1} ```

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Sample responsePOST

Shown before your first request. Add an API key and send a request to see the live response, status, latency, and headers.

{
  "code": 200,
  "msg": "OK",
  "data": {
    "seeds": [
      {
        "paper_id": "paper:seed-uuid",
        "primary_id": "europepmc:MED:17299597",
        "status": "ok"
      }
    ],
    "items": [
      {
        "paper": {
          "paper_id": "paper:neighbor-uuid",
          "primary_id": "europepmc:MED:10781045"
        },
        "rank": 1
      }
    ],
    "relations": [
      {
        "from_id": "paper:seed-uuid",
        "to_id": "paper:neighbor-uuid",
        "source_id": "europepmc",
        "source_url": "https://www.ebi.ac.uk/europepmc/webservices/rest/MED/17299597/references?format=json&page=1&pageSize=50",
        "retrieved_at": "2026-10-10T02:00:00Z"
      }
    ],
    "has_more": true,
    "next_cursor": "signed-owner-bound-cursor",
    "partial": false,
    "coverage": [
      {
        "source_id": "europepmc",
        "status": "ok"
      }
    ],
    "warnings": [],
    "usage": {
      "credits_charged": 3,
      "settlement_pending": false
    }
  }
}

Try the Retrieve paper citation graphs API

What a live request returned

14 Oct 2026: 1 items; 2 fields had a value in every checked item.

Observed request: POST /research/papers/related
Fields with a value in every checked item: paper, rank

Request: POST /research/papers/related
Cost: 3 credits/seed · up to 30
Auth: apiKey

Retrieve paper citation graphs API documentation Pricing

Prefilled cURL

curl 'https://api.crawlora.net/api/v1/research/papers/related' \
  -H "x-api-key: $CRAWLORA_API_KEY" \
  -X POST \
  --data '{}'

Request parameters

Parameter	Type	Required	Prefilled value	Description
request (body)	object	Yes		Seed IDs and graph direction, or cursor and optional limit

Example JSON response

{
  "code": 200,
  "msg": "OK",
  "data": {
    "seeds": [
      {
        "paper_id": "paper:seed-uuid",
        "primary_id": "europepmc:MED:17299597",
        "status": "ok"
      }
    ],
    "items": [
      {
        "paper": {
          "paper_id": "paper:neighbor-uuid",
          "primary_id": "europepmc:MED:10781045"
        },
        "rank": 1
      }
    ],
    "relations": [
      {
        "from_id": "paper:seed-uuid",
        "to_id": "paper:neighbor-uuid",
        "source_id": "europepmc",
        "source_url": "https://www.ebi.ac.uk/europepmc/webservices/rest/MED/17299597/references?format=json&page=1&pageSize=50",
        "retrieved_at": "2026-10-10T02:00:00Z"
      }
    ],
    "has_more": true,
    "next_cursor": "signed-owner-bound-cursor",
    "partial": false,
    "coverage": [
      {
        "source_id": "europepmc",
        "status": "ok"
      }
    ],
    "warnings": [],
    "usage": {
      "credits_charged": 3,
      "settlement_pending": false
    }
  }
}

Get paper references or citing papers

Response behavior

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{ "code": 200, "msg": "OK", "data": { "seeds": [ { "paper_id": "paper:seed-uuid", "primary_id": "europepmc:MED:17299597", "status": "ok" } ], "items": [ { "paper": { "paper_id": "paper:neighbor-uuid", "primary_id": "europepmc:MED:10781045" }, "rank": 1 } ], "relations": [ { "from_id": "paper:seed-uuid", "to_id": "paper:neighbor-uuid", "source_id": "europepmc", "source_url": "https://www.ebi.ac.uk/europepmc/webservices/rest/MED/17299597/references?format=json&page=1&pageSize=50", "retrieved_at": "2026-10-10T02:00:00Z" } ], "has_more": true, "next_cursor": "signed-owner-bound-cursor", "partial": false, "coverage": [ { "source_id": "europepmc", "status": "ok" } ], "warnings": [], "usage": { "credits_charged": 3, "settlement_pending": false } } }