Papers Search

{
  "legal": {
    "privacy": "https://paper-lookup-production-56b0.up.railway.app/privacy",
    "terms": "https://paper-lookup-production-56b0.up.railway.app/terms"
  },
  "results": [
    {
      "authors": [
        {
          "name": "A. Author",
          "orcid": null
        }
      ],
      "cited_by": 512,
      "container": "Water Research",
      "doi": "10.1016/j.watres.2018.05.060",
      "published": "2018-09-01",
      "title": "Microplastics in drinking water ...",
      "type": "journal-article",
      "url": "https://doi.org/10.1016/j.watres.2018.05.060"
    }
  ],
  "status": "ok",
  "total": 28674,
  "use_when": "Use when an agent must verify a citation or DOI, find papers on a topic, or get a paper's authors, journal, date, citation count and links."
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://paper-lookup-production-56b0.up.railway.app/v1/papers/search?query=microplastics+drinking+water'

# 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 - 'https://paper-lookup-production-56b0.up.railway.app/v1/papers/search?query=microplastics+drinking+water' \
  | 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 $0.005 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.005" });
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 $0.005 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fpaper-lookup-production-56b0.up.railway.app%2Fv1%2Fpapers%2Fsearch
const res = await pay("https://paper-lookup-production-56b0.up.railway.app/v1/papers/search?query=microplastics+drinking+water");
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 $0.005 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.005"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://paper-lookup-production-56b0.up.railway.app/v1/papers/search?query=microplastics+drinking+water")
    print(res.status_code, res.text)