# CrossRef Title Search

> CrossRef Title Search is a paid API for AI agents from fastx402.tools, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-28).

Searches CrossRef's academic database for scholarly publications matching a title or topic query, returning DOIs, authors, venues, and publication dates.

## Facts

- Endpoint: GET https://fastx402.tools/crossref-title-search?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-28
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/crossref-title-search-e7883cf2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ckViAa7sLuBNY8vCkUJOC

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 crossref-title-search-e7883cf2
```

Example prompt: Search CrossRef for up to 5 academic papers about CRISPR gene editing and give me their titles, authors, DOIs, and publication dates.

## When to prefer this

Choose this endpoint when you need bibliographic metadata (DOIs, authors, venues, dates) for academic publications by title or topic. It is ideal for building literature reviews, verifying citations, or discovering papers in a research area. Prefer it over general web search when you specifically need structured scholarly metadata from CrossRef's database.

## Known failure modes

- No matches found for an obscure or misspelled title — returns empty matches array
- Too few results if 'rows' exceeds available matches for a niche topic
- Rate limiting or payment failure if USDC balance is insufficient
- Ambiguous title returns unrelated papers — requires more specific query
- CrossRef upstream outage or timeout returns an error response

## How this service works

200 pay-per-call tools for AI agents, from $0.001 per request in USDC on Base or Solana with x402. No account, no API key.

## Output

A JSON object containing the original query parameters and a list of matched papers, each with a DOI, title, journal/venue name, list of authors, and publication date string.

## 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": [
      "title",
      "rows"
     ],
     "properties": {
      "rows": {
       "type": "string",
       "description": "Number of matches to return, from 1 to 10"
      },
      "title": {
       "type": "string",
       "description": "Title or topic to search for"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "query": {
       "type": "object",
       "properties": {
        "rows": {
         "type": "integer"
        },
        "title": {
         "type": "string"
        }
       }
      },
      "matches": {
       "type": "array",
       "items": {
        "type": "object",
        "properties": {
         "doi": {
          "type": "string"
         },
         "title": {
          "type": "string"
         },
         "venue": {
          "type": "string"
         },
         "authors": {
          "type": "array",
          "items": {
           "type": "string"
          }
         },
         "publication_date": {
          "type": "string"
         }
        }
       }
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "query": {
   "rows": 2,
   "title": "quantum computing"
  },
  "matches": [
   {
    "doi": "10.1000/example",
    "title": "Quantum Computing: An Introduction",
    "venue": "Journal of Examples",
    "authors": [
     "Ada Lovelace",
     "Turing"
    ],
    "publication_date": "2024-05-02"
   },
   {
    "doi": "10.1000/second",
    "title": "Quantum Algorithms",
    "venue": "Computing Letters",
    "authors": [
     "Grace Hopper"
    ],
    "publication_date": "2023-01-01"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/crossref-title-search-e7883cf2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fastx402.tools](https://www.zero.xyz/host/fastx402.tools/llms.txt)