# fittings DOI Metadata Resolver

> fittings DOI Metadata Resolver is a paid API for AI agents from fittings.sh, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-10).

Resolve a DOI to full bibliographic metadata including title, authors, journal, abstract, licence, funders, and citation counts via Crossref.

## Facts

- Endpoint: GET https://fittings.sh/v1/crossref/doi-metadata?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fittings-doi-metadata-resolver-7eb7be72
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JNXOPAwPU9ddPCm23Dnko

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 fittings-doi-metadata-resolver-7eb7be72
```

Example prompt: Can you look up the bibliographic metadata for the DOI 10.1038/nature12345 — I need the title, authors, journal, abstract, and how many times it's been cited?

## When to prefer this

Choose this endpoint when you need rich, structured bibliographic data for a known DOI, especially when you require abstract text, funder information, or citation counts in a single call. It wraps Crossref directly so it is best for journal articles, preprints, and book chapters indexed by Crossref. Prefer alternatives if you need full-text retrieval, PubMed-specific metadata, or data from sources outside Crossref (e.g., arXiv-only preprints).

## Known failure modes

- DOI not found in Crossref — returns a 404 or empty result
- Malformed DOI string causes a validation error
- Some fields (abstract, licence, funders) may be absent if not deposited by publisher
- Rate limiting may apply for high-volume usage
- doi.org redirect chain may fail for very new or retracted DOIs

## How this service works

Resolve a DOI to bibliographic metadata: title, authors, journal, dates, abstract, licence, funders and citation counts.

## Output

Returns structured bibliographic metadata for the resolved DOI, including title, author list, journal name, publication and online dates, abstract text, open-access licence information, funder names and grant IDs, and Crossref-sourced citation count.

## 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": [
      "doi"
     ],
     "properties": {
      "doi": {
       "type": "string",
       "description": "DOI, bare or as a doi.org URL"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fittings-doi-metadata-resolver-7eb7be72/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fittings.sh](https://www.zero.xyz/host/fittings.sh/llms.txt)