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/8/transactions` behind an x402 payment challenge. It is part of a broader platform that offers dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per request and settled in USDC on the Base network.
The specific endpoint listed here accepts HTTP POST requests and returns JSON. The x402 challenge advertises a maximum amount of 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913, which uses 6 decimals), equating to $0.02 per call. Payment is made via the x402 "exact" scheme to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a timeout of 300 seconds. No API keys or rate limits are advertised; access is granted purely through on-chain micropayment.
Documentation is extremely sparse. The crawled docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description of what the `/cards/8/transactions` resource actually returns or what POST body it expects. The endpoint name suggests card transaction data, but this cannot be confirmed from available material.
Capabilities
Use cases
- —Retrieving card transaction records via a single micropayment
- —Programmatic access to card-level transaction data without API key management
- —Agent-driven financial data retrieval settled on-chain
Fit
Best for
- —Developers wanting keyless, pay-per-call access to card transaction data
- —AI agents that can settle x402 USDC payments on Base
- —Users who prefer no-subscription, usage-based pricing
Not for
- —Users needing detailed API documentation or request/response schemas before integrating
- —High-volume batch processing where per-call micropayments add up
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/8/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is zero documentation on what the endpoint actually does, no request/response schema, and no examples. The docs pages are empty beyond a wallet-connect prompt. The specific resource path (/cards/8/transactions) is not explained anywhere in the crawled material.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or request/response schema provided; the purpose and expected input of /api/v1/cards/8/transactions is unknown.
- —The endpoint path references a hardcoded card ID (8), which may indicate a demo or placeholder resource.
- —Cannot confirm what data is returned or what POST body is expected.
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/cards/8/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 made to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout using the exact schemehttps://lowpaymentfee.com/api/v1/cards/8/transactions