Research Citation Velocity

{
  "billing": {
    "credits_charged": 1,
    "credits_remaining": 49
  },
  "capturedAt": "2026-05-23T06:00:00Z",
  "ok": true,
  "papers": [
    {
      "authors": [
        "First Author",
        "Second Author",
        "Third Author"
      ],
      "doi": "10.48550/arXiv.2503.00000",
      "latest_year_citations": 318,
      "latest_year_share": 0.772,
      "openalex_id": "W4400000000",
      "primary_affiliation": {
        "country_code": "US",
        "display_name": "Anthropic"
      },
      "rank": 1,
      "title": "Scaling Test-Time Compute Beyond Chain-of-Thought",
      "total_citations": 412,
      "venue": "arXiv",
      "year": 2025
    }
  ]
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://tensorfeed.ai/api/premium/research/citation-velocity'

# 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://tensorfeed.ai/api/premium/research/citation-velocity' \
  | 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 $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
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 $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Ftensorfeed.ai%2Fapi%2Fpremium%2Fresearch%2Fcitation-velocity
const res = await pay("https://tensorfeed.ai/api/premium/research/citation-velocity");
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 $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://tensorfeed.ai/api/premium/research/citation-velocity")
    print(res.status_code, res.text)