x402-gated card-transaction endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com exposes a card transactions resource at `/api/v1/cards/60/transactions` behind an x402 paywall. It accepts POST requests and requires an X-PAYMENT header carrying a USDC payment on the Base network. The x402 challenge advertises a maximum cost of 20,000 base units of USDC (0x8335…), which equals $0.02 per request (USDC uses 6 decimals).
The provider's landing page lists a broad catalog of pay-per-request APIs spanning data & analytics, AI/ML inference (sentiment, summarization, classification, embeddings), finance/Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation) — all priced at $0.02 per call. However, the specific endpoint being listed here (`/api/v1/cards/60/transactions`) is not explicitly documented on the landing page, and no detailed API documentation, request/response schemas, or example payloads were found in the crawl. The docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content.
Because the endpoint path suggests card transaction data and the provider labels it "Premium API Access" without further elaboration, the exact functionality remains unclear. The x402 challenge confirms the endpoint is live and accepting payment-gated POST requests, but consumers should be aware that documentation is essentially absent.
Capabilities
Use cases
- —Submitting or retrieving card transaction records via a pay-per-call model
- —Integrating card transaction data into agent workflows without API keys
- —Programmatic access to card-level transaction information settled in USDC on Base
Fit
Best for
- —Agents or services that need keyless, pay-per-request card transaction access
- —Developers experimenting with x402 payment protocol integrations
- —Workflows requiring on-chain micropayment-gated API calls
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume batch processing where $0.02/request adds up quickly
- —Anyone needing non-USDC or non-Base-network payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/60/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and confirms pricing and payment details, but there is zero documentation for this specific endpoint — no request/response schema, no examples, no explanation of what 'cards/60/transactions' actually returns. The docs pages are empty. This is effectively a stub listing.
Warnings
- —No API documentation found — docs, pricing, API, and README pages all render only a wallet-connect prompt with no content.
- —The specific endpoint /api/v1/cards/60/transactions is not listed on the provider's landing page catalog, making its purpose unclear.
- —No request or response schema is available; consumers must discover the API contract by trial and error.
- —The endpoint path references a hardcoded card ID (60), which may not be generalizable.
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/cards/60/transactions
- —The provider lists all APIs at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/cards/60/transactions
- —Docs, API, pricing, and README pages returned only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs