Research Crossref Work Search

{
  "data": {
    "documentation": "https://www.crossref.org/documentation/retrieve-metadata/rest-api/",
    "limitations": [
      "Demonstration metadata only; paid calls return current publisher-deposited re...",
      "Abstracts and full text are deliberately excluded."
    ],
    "metadataLicense": {
      "abstractsReturned": false,
      "name": "Open bibliographic metadata / Crossref-generated data CC0",
      "url": "https://www.crossref.org/documentation/retrieve-metadata/"
    },
    "query": {
      "bibliographic": "agentic commerce payment protocols",
      "publishedFrom": null,
      "publishedUntil": null,
      "sortBy": "relevance",
      "workType": "journal-article"
    },
    "results": [
      {
        "authors": [
          {
            "affiliations": [
              "Example Institute"
            ],
            "family": "Example",
            "given": "Ada",
            "name": "Ada Example",
            "orcid": null
          }
        ],
        "doi": "10.1000/apiacre.example",
        "publishedDate": "2026-08-20",
        "title": "A bounded example scholarly work",
        "type": "journal-article"
      }
    ],
    "resultsReturned": 1,
    "retrievedAt": "2026-08-20T12:00:00+00:00",
    "source": "https://api.crossref.org/works",
    "totalResults": 1
  },
  "meta": {
    "cached": false,
    "duration_ms": 42,
    "next_actions": [
      {
        "method": "POST",
        "path": "/v1/research/crossref-doi-metadata",
        "reason": "Resolve one selected scholarly-search candidate into a focused current DOI me...",
        "service": "research.crossref-doi-metadata",
        "title": "Crossref DOI metadata enrichment"
      }
    ],
    "sources": [],
    "warnings": []
  },
  "request_id": "018f1f54-7f38-7ba2-8dc3-5f90272d9f1a",
  "service": "research.crossref-work-search",
  "version": "1"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://apiacre.com/v1/research/crossref-work-search' \
  -H 'content-type: application/json' \
  --data-raw '{"max_results":5,"query":"agentic commerce payment protocols","sort_by":"relevance","work_type":"journal-article"}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://apiacre.com/v1/research/crossref-work-search' \
  -H 'content-type: application/json' \
  --data-raw '{"max_results":5,"query":"agentic commerce payment protocols","sort_by":"relevance","work_type":"journal-article"}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.008 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.008" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.008 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapiacre.com%2Fv1%2Fresearch%2Fcrossref-work-search&method=POST
const res = await pay("https://apiacre.com/v1/research/crossref-work-search", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "max_results": 5,
    "query": "agentic commerce payment protocols",
    "sort_by": "relevance",
    "work_type": "journal-article"
  }),
});
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.008 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.008"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://apiacre.com/v1/research/crossref-work-search",
        json={
            "max_results": 5,
            "query": "agentic commerce payment protocols",
            "sort_by": "relevance",
            "work_type": "journal-article",
        },
    )
    print(res.status_code, res.text)