# API Acre Crossref Work Search

> API Acre Crossref Work Search is a paid API for AI agents from apiacre.com, paid per call via x402, $0.008/call, status unknown (last checked 2026-09-14).

Search Crossref's open bibliographic metadata by title, author, DOI fragment, or citation query and return normalized publication, author, citation, license, and update metadata.

## Facts

- Endpoint: POST https://apiacre.com/v1/research/crossref-work-search
- Price: $0.008/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-acre-crossref-work-search-be741e0b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_a7qnWbucm9lyc77Qm35mq

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 api-acre-crossref-work-search-be741e0b -d '<json body>'
```

Example prompt: Search Crossref for up to 10 journal articles about transformer neural networks published between 2020 and 2023, sorted by most cited, and return the normalized bibliographic metadata.

## When to prefer this

Choose this endpoint when you need open, structured bibliographic metadata from Crossref — including DOIs, authors, citation counts, and license info — without needing abstracts or full text. Prefer it over general web search when you want normalized, machine-readable scholarly metadata across all work types (journal articles, datasets, dissertations, preprints, etc.) and need filtering by date range, work type, or sort order.

## Known failure modes

- Query too vague or short returns low-relevance results
- Crossref has no matching records for an obscure DOI fragment
- published_from or published_until in unsupported date format causes validation error
- max_results set too high may be capped or slow
- Work type filter excludes relevant results if incorrectly specified

## How this service works

Search open Crossref bibliographic metadata by title, author, DOI fragment, or citation and return bounded normalized publication, author, citation, license, and update metadata without abstracts or full text.

## Output

Returns bounded normalized records containing publication metadata (title, DOI, work type, publication date), author details, citation counts, license information, and update metadata — without abstracts or full text.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "query": {
   "type": "string"
  },
  "sort_by": {
   "enum": [
    "relevance",
    "newest",
    "most_cited"
   ],
   "type": "string"
  },
  "work_type": {
   "anyOf": [
    {
     "enum": [
      "book",
      "book-chapter",
      "dataset",
      "dissertation",
      "journal-article",
      "monograph",
      "posted-content",
      "proceedings-article",
      "report",
      "standard"
     ],
     "type": "string"
    },
    {
     "type": "null"
    }
   ]
  },
  "max_results": {
   "type": "integer"
  },
  "published_from": {
   "anyOf": [
    {
     "type": "string"
    },
    {
     "type": "null"
    }
   ]
  },
  "published_until": {
   "anyOf": [
    {
     "type": "string"
    },
    {
     "type": "null"
    }
   ]
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "query": {
    "sortBy": "relevance",
    "workType": "journal-article",
    "bibliographic": "agentic commerce payment protocols",
    "publishedFrom": null,
    "publishedUntil": null
   },
   "source": "https://api.crossref.org/works",
   "results": [
    {
     "doi": "10.1000/apiacre.example",
     "type": "journal-article",
     "title": "A bounded example scholarly work",
     "authors": [
      {
       "name": "Ada Example",
       "given": "Ada",
       "orcid": null,
       "family": "Example",
       "affiliations": [
        "Example Institute"
       ]
      }
     ],
     "publishedDate": "2026-08-20"
    }
   ],
   "limitations": [
    "Demonstration metadata only; paid calls return current publisher-deposited re...",
    "Abstracts and full text are deliberately excluded."
   ],
   "retrievedAt": "2026-08-20T12:00:00+00:00",
   "totalResults": 1,
   "documentation": "https://www.crossref.org/documentation/retrieve-metadata/rest-api/",
   "metadataLicense": {
    "url": "https://www.crossref.org/documentation/retrieve-metadata/",
    "name": "Open bibliographic metadata / Crossref-generated data CC0",
    "abstractsReturned": false
   },
   "resultsReturned": 1
  },
  "meta": {
   "cached": false,
   "sources": [],
   "warnings": [],
   "duration_ms": 42,
   "next_actions": [
    {
     "path": "/v1/research/crossref-doi-metadata",
     "title": "Crossref DOI metadata enrichment",
     "method": "POST",
     "reason": "Resolve one selected scholarly-search candidate into a focused current DOI me...",
     "service": "research.crossref-doi-metadata"
    }
   ]
  },
  "service": "research.crossref-work-search",
  "version": "1",
  "request_id": "018f1f54-7f38-7ba2-8dc3-5f90272d9f1a"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-acre-crossref-work-search-be741e0b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from apiacre.com](https://www.zero.xyz/host/apiacre.com/llms.txt)