x402basequality 0.30

x402-gated premium API endpoint on Base, pay-per-call with USDC.

Price
0.02 USDC / call
Protocol
x402
Verified
no
Endpoint
https://lowpaymentfee.com/api/v1/cards/15

What it does

This endpoint at `/api/v1/cards/15` is part of the lowpaymentfee.com platform, a collection of x402-protocol pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. The specific `/api/v1/cards/15` resource 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 gated behind x402 micropayments settled in USDC on the Base network.

The x402 challenge confirms the endpoint is live and accepts POST requests. The maximum amount required is 20,000 base units of USDC (the asset at `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913` on Base). Since USDC uses 6 decimals, this translates to $0.02 per request, consistent with the platform's advertised flat pricing of $0.02/request across all endpoints. Payment is made via the `exact` scheme to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3`, with a 300-second timeout.

The platform advertises no API keys, no rate limits, and instant access. However, documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what `/api/v1/cards/15` actually returns. The endpoint's purpose must be inferred entirely from its title, which is generic.

Capabilities

x402-paymentusdc-basepay-per-requestpost-methodmicropayment

Use cases

  • —Accessing a premium data resource via a single x402 micropayment
  • —Agent-driven API consumption without API keys or subscriptions
  • —Programmatic pay-per-use access on the Base L2 network

Fit

Best for

  • —Developers or agents wanting keyless, pay-per-call API access
  • —Testing x402 protocol integrations on Base
  • —Low-commitment API usage with no subscriptions

Not for

  • —Users who need detailed documentation or OpenAPI specs before integrating
  • —High-volume use cases where per-request pricing may add up
  • —Anyone needing clarity on what the endpoint actually returns

Quick start

# The endpoint requires an X-PAYMENT header with a valid x402 payment proof.
curl -X POST https://lowpaymentfee.com/api/v1/cards/15 \
  -H "Content-Type: application/json" \
  -H "X-PAYMENT: <x402_payment_token>"

Endpoint

URLhttps://lowpaymentfee.com/api/v1/cards/15
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 there is no documentation, no schema, no request/response examples, and the endpoint's actual functionality ('Premium API Access' for /api/v1/cards/15) is completely opaque. All non-landing pages return only 'Connect wallet' with no content.

Warnings

  • —The exact functionality of /api/v1/cards/15 is unknown — 'Premium API Access' is the only description available.
  • —No OpenAPI schema, request format, or response format is documented anywhere.
  • —All documentation pages (docs, API, pricing, README) render only 'Connect wallet' with no useful content.
  • —The endpoint path '/api/v1/cards/15' suggests a resource-specific lookup but no details are available on what 'cards' represents.

Citations

Provenance

Indexed fromx402_bazaar
Enriched2026-04-19 02:52:16Z · anthropic/claude-opus-4.6 · v2
First seen2026-04-18
Last seen2026-04-22

Agent access

JSONhttps://clawmart.sh/api/listings/HTgFnK
x402-gated premium API endpoint on Base, pay-per-call with USDC. — Clawmart · Clawmart