x402basequality 0.30

x402-gated premium API endpoint on Base, pay $0.02 per request in USDC.

Price
0.02 USDC / call
Protocol
x402
Verified
no
Endpoint
https://lowpaymentfee.com/api/v1/cards/57

What it does

This endpoint at `/api/v1/cards/57` is part of the lowpaymentfee.com platform, which offers a collection of x402-protocol pay-per-request APIs spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. The specific resource at `/cards/57` is labeled "Premium API Access" but its exact functionality is not documented beyond that label. It is one of many endpoints on the platform, all priced uniformly at $0.02 per call.

Payment is handled via the x402 protocol on the Base network using USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`). The challenge advertises a `maxAmountRequired` of 20,000 base units, which at 6 decimals equals $0.02. No API keys or rate limits are required — callers simply attach an `X-PAYMENT` header with a valid x402 payment proof. The endpoint accepts HTTP POST requests and returns `application/json`.

The broader platform lists endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, conversion, and data export, all at the same $0.02 price point. However, documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further technical detail. Without documentation or schema definitions for request/response bodies, it is unclear what parameters `/api/v1/cards/57` expects or what it returns.

Capabilities

x402-paymentusdc-basepay-per-requestjson-apino-api-keyhttp-post

Use cases

  • —Accessing a premium data or service endpoint with per-request USDC micropayments
  • —Integrating pay-per-call APIs without managing API keys or subscriptions
  • —Agent-driven API consumption using x402 payment protocol

Fit

Best for

  • —Developers wanting zero-commitment pay-per-use API access
  • —AI agents that can settle x402 payments on Base
  • —Users who prefer crypto micropayments over subscription billing

Not for

  • —Anyone needing detailed API documentation or request/response schemas before integrating
  • —Use cases requiring free or high-volume bulk access at discounted rates

Quick start

curl -X POST https://lowpaymentfee.com/api/v1/cards/57 \
  -H "Content-Type: application/json" \
  -H "X-PAYMENT: <x402-payment-proof>"

Endpoint

URLhttps://lowpaymentfee.com/api/v1/cards/57
Transporthttp
Protocolx402
Pay to0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3
CurrencyUSD COIN

Quality

0.30/ 1.00

The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but the specific functionality of /api/v1/cards/57 is undocumented. No request/response schemas, no examples, and all documentation pages return only 'Connect wallet' with no content. This is effectively a stub listing.

Warnings

  • —The exact purpose and functionality of /api/v1/cards/57 ('Premium API Access') is not documented anywhere in the crawled material.
  • —All documentation pages (docs, API, pricing, README) render only 'Connect wallet' with no technical content.
  • —No request or response schema is available — callers cannot know what parameters to send or what to expect back.
  • —The endpoint path '/api/v1/cards/57' does not match any of the listed API categories on the homepage, suggesting it may be a test or placeholder resource.

Citations

Provenance

Indexed fromx402_bazaar
Enriched2026-04-19 03:01:03Z · anthropic/claude-opus-4.6 · v2
First seen2026-04-18
Last seen2026-04-22

Agent access

JSONhttps://clawmart.sh/api/listings/kPruJT
x402-gated premium API endpoint on Base, pay $0.02 per request in USDC. — Clawmart · Clawmart