x402-gated card-transactions endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com exposes a POST resource at `/api/v1/cards/66/transactions` behind an x402 payment challenge. The x402 challenge advertises a maximum cost of 20,000 base units of USDC (0x8335…2913 on Base network), which equals $0.02 per request given USDC's 6 decimals. Payment is settled on-chain on Base to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3. No API keys or rate limits are advertised; access is granted purely via the x402 payment header.
The specific endpoint path (`/cards/66/transactions`) suggests it returns or creates transaction records associated with a particular card entity (ID 66), but no further documentation, request schema, or response schema is available. The provider's landing page lists a broad catalog of endpoints spanning data analytics, AI/ML inference, finance, crypto, infrastructure utilities, and more — all priced at $0.02 per request via x402 on Base. However, the `/cards/66/transactions` path does not appear in the publicly listed catalog, so its exact functionality is unclear.
The docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no substantive documentation. Without request/response schemas or usage examples, integrators will need to experiment with the endpoint to determine accepted input fields and output format. The endpoint is confirmed live (402 challenge returned successfully).
Capabilities
Use cases
- —Retrieving or creating transaction records for a specific card entity via pay-per-call USDC payments
- —Integrating card transaction data into agent workflows without API key management
- —Programmatic access to card-level transaction data settled on Base L2
Fit
Best for
- —Developers wanting keyless, pay-per-request card transaction access
- —AI agents that can settle x402 USDC payments on Base
- —Prototyping integrations where no subscription commitment is desired
Not for
- —Production use requiring documented request/response schemas and SLAs
- —High-volume batch processing where per-call pricing may be costly
- —Users who need detailed API documentation before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/66/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no request/response schema, and the specific /cards/66/transactions path is not listed in the provider's public catalog. Functionality must be guessed from the URL path alone.
Warnings
- —No request or response schema available — input/output format is unknown
- —The /cards/66/transactions path does not appear in the provider's public API catalog
- —All documentation pages (docs, pricing, API, README) render only 'Connect wallet' with no content
- —The purpose of 'cards/66' is unclear — it may be a demo, placeholder, or internal resource
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/cards/66/transactions
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC contract address on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/66/transactions