# SYNTHORA Crossref DOI Metadata Resolver

> SYNTHORA Crossref DOI Metadata Resolver is a paid API for AI agents from crossref-work-by-doi.hergertsynthora.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Resolves a DOI to its full Crossref registration metadata, returning title, authors, journal, publisher, funder, license, and reference list as structured JSON.

## Facts

- Endpoint: POST https://crossref-work-by-doi.hergertsynthora.com/service
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synthora-crossref-doi-metadata-resolver-cbde7b4f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tM57GiSUzRa3Ia_77nn9b

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 synthora-crossref-doi-metadata-resolver-cbde7b4f -d '<json body>'
```

Example prompt: Can you look up the full metadata for the DOI 10.1038/nature12373 — I need the title, authors, journal, publisher, and publication date from Crossref?

## When to prefer this

Use this endpoint when you need authoritative bibliographic metadata for a specific DOI sourced directly from Crossref, the canonical DOI registration authority for scholarly publishing. Prefer it over web-scraping or publisher-specific APIs when you need structured, normalized data (authors, journal, funder, license) that works across publishers. Ideal for agent-driven citation verification, bibliographic pipeline enrichment, and reference list resolution where reliability and structured JSON output matter more than full-text access.

## Known failure modes

- DOI not registered with Crossref — returns not-found or empty result
- Malformed DOI string — may fail to resolve or return an error
- Abstract not available — abstract field returns null for many records
- Reference list not populated — not all Crossref records include references
- Network or upstream Crossref API timeout — service may return an error
- ISSN or funder data missing for older or incomplete records

## How this service works

Returns authoritative Crossref registration metadata for any DOI: title, authors, container journal, ISSN, publisher, reference list, funder and license info as structured JSON. A core keyless enrichment endpoint for autonomous research agents and agent-to-agent citation-verification and bibliographic pipelines. First 3 calls FREE per wallet — send header X-WALLET: 0x<addr>. No charge on upstream failure.

## Output

A JSON object containing: the DOI, canonical URL, document type (e.g. journal-article), title, list of author names, journal/container name, abstract (if available), publisher name, publication date, and provenance indicating the data came from the Crossref API. The response wraps results under an 'ok' flag and a 'result' object.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "doi": {
   "type": "string",
   "description": "doi"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "niche": "crossref-work-by-doi",
  "result": {
   "doi": "10.1038/nature12373",
   "url": "https://doi.org/10.1038/nature12373",
   "type": "journal-article",
   "title": "Nanometre-scale thermometry in a living cell",
   "authors": [
    "G. Kucsko",
    "P. C. Maurer",
    "N. Y. Yao",
    "M. Kubo",
    "H. J. Noh",
    "P. K. Lo",
    "H. Park",
    "M. D. Lukin"
   ],
   "journal": "Nature",
   "abstract": null,
   "publisher": "Springer Science and Business Media LLC",
   "published_date": "2013-08"
  },
  "provenance": {
   "url": "https://api.crossref.org/works",
   "source": "Crossref DOI Metadata Resolver"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synthora-crossref-doi-metadata-resolver-cbde7b4f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from crossref-work-by-doi.hergertsynthora.com](https://www.zero.xyz/host/crossref-work-by-doi.hergertsynthora.com/llms.txt)