x402basequality 0.35

x402-gated API suite on Base: analytics, AI, finance, and utility endpoints at $0.02/request.

Price
0.02 USDC / call
Protocol
x402
Verified
no
Endpoint
https://lowpaymentfee.com/api/v1/carts/49

What it does

lowpaymentfee.com offers a collection of x402-protocol pay-per-request API endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/carts/49` is listed as "Premium API Access" and returns a standard x402 challenge requiring payment of up to 20,000 base units of USDC (0.02 USD) per call. The site advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.

The broader platform groups endpoints into four categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All listed endpoints share the same $0.02 per-request pricing.

Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The `/api/v1/carts/49` endpoint itself is live and responds with a well-formed x402 challenge, but without documentation it is unclear what this specific cart endpoint accepts as input or returns as output. Prospective users should be aware that the lack of documentation makes integration difficult without experimentation.

Capabilities

x402-paymentusdc-settlementbase-networkpay-per-requestno-api-keyjson-responsehttp-post

Use cases

  • —Paying per-request for API access without managing API keys or subscriptions
  • —Programmatic agent-driven API consumption using x402 payment protocol on Base
  • —Accessing a variety of utility, analytics, AI, and finance endpoints with USDC micropayments

Fit

Best for

  • —Developers or agents wanting key-free, pay-as-you-go API access
  • —x402-compatible wallets and agents on the Base network
  • —Low-volume or experimental usage where per-call pricing is preferable to subscriptions

Not for

  • —Users needing detailed API documentation or guaranteed SLAs before integrating
  • —High-volume production workloads where per-request costs add up without volume discounts
  • —Users without USDC on Base or unfamiliar with x402 payment protocol

Quick start

# 1. The endpoint returns a 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/carts/49
# Response: 402 with x402 challenge (maxAmountRequired: 20000 USDC base units = $0.02)

# 2. Attach a valid X-PAYMENT header with your x402 payment proof:
curl -X POST https://lowpaymentfee.com/api/v1/carts/49 \
  -H "X-PAYMENT: <x402-payment-proof>"

Example

Response

{
  "error": "X-PAYMENT header is required",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3",
      "scheme": "exact",
      "network": "base",
      "mimeType": "application/json",
      "resource": "https://lowpaymentfee.com/api/v1/carts/49",
      "description": "Premium API Access",
      "maxAmountRequired": "20000",
      "maxTimeoutSeconds": 300
    }
  ],
  "x402Version": 1
}

Endpoint

URLhttps://lowpaymentfee.com/api/v1/carts/49
Transporthttp
Protocolx402
Pay to0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3
CurrencyUSD COIN

Quality

0.35/ 1.00

The endpoint is live and returns a valid x402 challenge, but there is zero documentation beyond the landing page listing. No OpenAPI spec, no request/response examples, and no explanation of what /api/v1/carts/49 actually does. The 'Premium API Access' label is generic and uninformative.

Warnings

  • —No API documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet' with no content
  • —No OpenAPI or schema specification found for any endpoint
  • —The purpose of /api/v1/carts/49 ('Premium API Access') is entirely unclear — no description of inputs or outputs
  • —Cannot verify what data or functionality any of the advertised endpoints actually provide

Citations

Provenance

Indexed fromx402_bazaar
Enriched2026-04-18 23:18:47Z · anthropic/claude-opus-4.6 · v2
First seen2026-04-18
Last seen2026-04-23

Agent access

JSONhttps://clawmart.sh/api/listings/FhETyc
x402-gated API suite on Base: analytics, AI, finance, and utility endpoints at $0.02/request. — Clawmart · Clawmart