Developer Tool · x402 · early usage

Smart, auto-routed research paper search

by api.kadec0.xyz · discovered, not yet claimed by its owner · updated 2026-10-12

30d calls140

30d payers3

MethodGET

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Smart, auto-routed research paper search. A broad field term is grounded against the OpenAlex taxonomy and returned as a coherent field cluster; a natural-language question runs hybrid retrieval over OpenAlex and Semantic Scholar with reciprocal rank fusion and a SPECTER2 embedding rerank. The response exposes the routing decision, and each paper carries title, authors, year, venue, citation count, DOI, and a relevance score. Keyless.

Tags: semantic-search · smart-search · hybrid-search · question-search · paper-search · bazaar

Call contract

Method: GET
Input: query parameters
Output: json
Last paid call: 2026-10-12

Input example from Bazaar metadata

{
  "maxItems": "15",
  "q": "does zone 2 training improve mitochondrial density in older adults"
}

Output example

{
  "count": 1,
  "items": [
    {
      "count": 15,
      "grounding": null,
      "mode": "hybrid",
      "query": "does zone 2 training improve mitochondrial density in older adults",
      "results": [
        {
          "citationCount": 210,
          "score": 0.0163,
          "specterCosine": 0.71,
          "title": "Exercise training and mitochondrial biogenesis...",
          "type": "paper",
          "year": 2019
        }
      ],
      "routing": {
        "embedded": 18,
        "fusion": "openalex-only",
        "isQuestion": true,
        "openAlexHits": 30,
        "reranked": true,
        "s2Hits": 0,
        "wordCount": 10
      },
      "type": "smart_search"
    }
  ]
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/26301.json for the price and payment options.
Pay. Call GET https://api.kadec0.xyz/v1/smart-search. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.02 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Demand: 140 calls · 3 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.02	0x4df66B6c140778fe0717880A7c6dDE5Ea53AcDeA	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x4df66B6c140778fe0717880A7c6dDE5Ea53AcDeA",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "20000",
    "amountUsd": 0.02,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {},
  "type": "string"
}

Examples

curl

curl "https://api.kadec0.xyz/v1/smart-search"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://api.kadec0.xyz/v1/smart-search");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://api.kadec0.xyz/v1/smart-search")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: api.kadec0.xyz
Endpoint: https://api.kadec0.xyz/v1/smart-search
Machine-readable: /resources/26301.json