# Rotary Agency CrossRef Lookup

> Rotary Agency CrossRef Lookup is a paid API for AI agents from rotaryagency.uk, paid per call via x402, $0.002/call, status down (last checked 2026-10-25).

Proxies the CrossRef API to retrieve scholarly metadata for publications, journals, and DOIs via a paid-per-call endpoint

## Facts

- Endpoint: GET https://rotaryagency.uk/api/free/crossref?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-10-25
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/rotary-agency-crossref-lookup-c96b0e6f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_AiFLG13NDX1QMRSQ-FlUu

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 rotary-agency-crossref-lookup-c96b0e6f
```

Example prompt: Can you look up the CrossRef metadata for the DOI 10.1038/nature12345 and tell me the title, authors, publication date, and journal?

## When to prefer this

Use this endpoint when you need programmatic, per-call access to CrossRef bibliographic metadata — especially when the underlying CrossRef API is unavailable or you want a simple monetized proxy with x402 payment support. Prefer this over direct CrossRef access when operating in an agentic payment-enabled environment that already handles x402 micropayments.

## Known failure modes

- DOI not found in CrossRef registry returns empty or error response
- Malformed DOI input causes query failure
- CrossRef rate limits or downtime propagate as errors
- Ambiguous title queries return multiple or irrelevant results
- Payment failure at $0.002/call blocks request before reaching CrossRef

## How this service works

Free-source data APIs (100% margin, no proxy, $0.002/call): ...

## Output

Returns a structured JSON object from CrossRef containing bibliographic metadata such as DOI, title, authors, journal name, ISSN, publisher, publication date, abstract, citation count, and related identifiers, formatted as CrossRef's standard work record.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "varies": "endpoint-specific structured JSON"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rotary-agency-crossref-lookup-c96b0e6f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from rotaryagency.uk](https://www.zero.xyz/host/rotaryagency.uk/llms.txt)