x402basequality 0.35

Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.

Price
0.02 USDC / call
Protocol
x402
Verified
no
Endpoint
https://lowpaymentfee.com/api/v1/payments/137

What it does

This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. It is one of many endpoints offered by the provider, which spans categories including data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, payable in USDC on the Base network with no API keys, rate limits, or commitments required.

The specific endpoint `/api/v1/payments/137` returns a valid x402 challenge (HTTP 402) requesting payment of up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) to wallet `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` on Base. The payment scheme is "exact" with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.

However, the specific functionality behind this particular endpoint (`/api/v1/payments/137`) is not documented beyond the generic label "Premium API Access." The provider's landing page lists many other endpoints with clear descriptions (metrics, sentiment analysis, summarization, etc.), but this particular path does not appear among them. Documentation pages (/docs, /pricing, /README) all returned only a "Connect wallet" prompt with no substantive content. Without further documentation, the exact data or service returned after payment is unknown.

Capabilities

x402-paymentusdc-basepay-per-requestjson-responseno-api-keypost-method

Use cases

  • —Programmatic access to a paid API endpoint without traditional API key registration
  • —Agent-driven workflows that need to pay per call using USDC on Base
  • —Testing x402 payment protocol integrations

Fit

Best for

  • —Developers or agents wanting keyless, pay-per-use API access
  • —x402 protocol experimentation on Base
  • —Low-cost micropayment API calls at $0.02 each

Not for

  • —Users who need detailed documentation about what the endpoint returns before paying
  • —High-volume use cases where per-request crypto payments add latency
  • —Users without USDC on the Base network

Quick start

# The endpoint requires an X-PAYMENT header with a valid x402 payment proof.
# Without payment, it returns a 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/payments/137
# Response: 402 with x402 challenge JSON describing USDC payment on Base ($0.02)

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/payments/137",
      "description": "Premium API Access",
      "maxAmountRequired": "20000",
      "maxTimeoutSeconds": 300
    }
  ],
  "x402Version": 1
}

Endpoint

URLhttps://lowpaymentfee.com/api/v1/payments/137
Transporthttp
Protocolx402
Pay to0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3
CurrencyUSD COIN

Quality

0.35/ 1.00

The endpoint is live and returns a valid x402 challenge, but the specific functionality behind /api/v1/payments/137 is undocumented. No OpenAPI schema, no response examples, and all doc pages return only 'Connect wallet' with no content. The label 'Premium API Access' is generic and uninformative.

Warnings

  • —The exact data or service returned after successful payment is unknown — 'Premium API Access' is not described anywhere in the crawled documentation.
  • —This specific path (/api/v1/payments/137) does not appear in the provider's listed API catalog on the landing page.
  • —All documentation pages (/docs, /pricing, /README, /api) returned only a 'Connect wallet' prompt with no substantive content.
  • —No OpenAPI spec or response schema available.

Citations

Provenance

Indexed fromx402_bazaar
Enriched2026-04-19 06:32:31Z · anthropic/claude-opus-4.6 · v2
First seen2026-04-18
Last seen2026-04-22

Agent access

JSONhttps://clawmart.sh/api/listings/NkCwVn
Pay-per-call premium API access on Base via x402 — $0.02/request in USDC. — Clawmart · Clawmart