x402-gated card-transactions endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com exposes a card-transactions resource at `/api/v1/cards/64/transactions` behind the x402 payment protocol. It accepts POST requests and requires an X-PAYMENT header carrying a USDC payment on the Base network. The x402 challenge advertises a maximum amount of 20,000 base units of USDC (0x8335…), which equals $0.02 per call (USDC uses 6 decimals). Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The provider's landing page lists a broad catalog of x402-gated APIs spanning data/analytics, AI/ML, finance/Web3, and infrastructure utilities, all priced at $0.02 per request. This specific endpoint appears to fall under a "cards" resource path, but the provider's existing description simply labels it "Premium API Access" without further detail on what data or functionality the transactions endpoint returns. No OpenAPI schema, request/response examples, or detailed documentation were found in the crawl — the docs, API, pricing, and README pages all rendered only a "Connect wallet" prompt.
Because the endpoint is live (returns a well-formed 402 challenge) but lacks any documentation about request parameters or response format, agents should treat this as a functional but poorly documented service. The pricing model is straightforward: no API keys, no rate limits, pay-per-call via x402 on Base.
Capabilities
Use cases
- —Retrieving transaction data for a specific card via a pay-per-call model
- —Integrating card transaction lookups into agent workflows without API key management
- —Paying per request in USDC on Base for financial data access
Fit
Best for
- —Agents that can settle x402 payments in USDC on Base
- —Use cases needing keyless, pay-per-call card transaction data
- —Developers exploring x402 protocol integrations
Not for
- —Users who need detailed API documentation or response schemas before integrating
- —High-volume batch processing where per-call pricing may add up
- —Non-crypto users who cannot settle payments on Base network
Quick start
# The endpoint requires an x402 X-PAYMENT header with USDC on Base.
# 1. POST to the endpoint without payment to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/cards/64/transactions
# 2. Parse the 402 response, construct payment proof, and resend:
curl -X POST https://lowpaymentfee.com/api/v1/cards/64/transactions \
-H "X-PAYMENT: <signed-payment-payload>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is zero documentation on request parameters, response schema, or what 'card transactions' actually returns. The docs pages are empty. This is effectively a stub listing.
Warnings
- —No OpenAPI or request/response schema available — the actual functionality of this endpoint is unknown.
- —All documentation pages (docs, API, pricing, README) returned only a 'Connect wallet' prompt with no useful content.
- —The endpoint path references 'cards/64/transactions' but no explanation of what card 64 represents or what data is returned.
- —The provider lists many API categories on the landing page but this specific endpoint's purpose is unclear beyond the generic 'Premium API Access' label.
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/cards/64/transactions
- —All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeouthttps://lowpaymentfee.com/api/v1/cards/64/transactions