# Research Paper Search (Crossref)

> Research Paper Search (Crossref) is a paid API for AI agents from bess-x402.onrender.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-30).

Search published academic research papers and articles across all publishers via Crossref, returning title, authors, journal, year, DOI, citation count, and abstract.

## Facts

- Endpoint: GET https://bess-x402.onrender.com/v1/research/papers?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/research-paper-search-crossref-aafca39d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XdqSpPdiLbM41jMqXLs2Q

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-search-crossref-aafca39d
```

Example prompt: Search for the top 10 most-cited research papers on transformer neural networks, sorted by citations, and give me the title, authors, DOI, and abstract for each.

## When to prefer this

Use this endpoint when you need to find, cite, or reference published academic research across any discipline. It's ideal for literature reviews, fact-checking with scholarly sources, or retrieving DOIs and bibliographic metadata. Prefer this over general web search when you specifically need peer-reviewed or formally published material indexed by Crossref.

## Known failure modes

- No results returned for very obscure or misspelled queries
- Abstract field may be missing for some papers not indexed by Crossref
- Citation counts may lag behind real-time totals
- Rate limiting or timeout if the Crossref upstream API is slow
- Invalid sort parameter value returns an error

## How this service works

Search published research papers and articles across all publishers (Crossref): title, authors, journal, year, DOI, citation count and abstract, by relevance, date or citations. Use to find and cite sources.

## Output

Returns a list of academic papers matching the query, each containing title, authors, journal name, publication year, DOI, citation count, and abstract. Results can be sorted by relevance, date, or citation count, with up to 50 results per call.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "q"
     ],
     "properties": {
      "q": {
       "type": "string",
       "description": "Title, topic or author words"
      },
      "sort": {
       "type": "string",
       "description": "relevance, date or citations"
      },
      "limit": {
       "type": "integer",
       "description": "Maximum number of results (1-50)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/research-paper-search-crossref-aafca39d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from bess-x402.onrender.com](https://www.zero.xyz/host/bess-x402.onrender.com/llms.txt)