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/47/transactions` behind an x402 payment challenge. The x402 challenge confirms the endpoint is live and accepts payments in USDC on the Base network using the "exact" scheme. The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02 per request.
The broader lowpaymentfee.com platform advertises a suite of pay-per-request APIs spanning data & analytics, AI/ML inference (sentiment analysis, 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 request with no API keys, no rate limits, and no commitments. However, the specific endpoint being listed here (`/api/v1/cards/47/transactions`) is not explicitly described on the landing page among the advertised APIs. Its path suggests it relates to retrieving or creating transactions for a specific card resource (card ID 47), but no documentation, request schema, or response schema is available to confirm its exact behavior.
Without OpenAPI specs, example requests/responses, or dedicated documentation (the /docs, /pricing, and /README pages all returned only a "Connect wallet" stub), the precise functionality of this endpoint remains unclear. The payment infrastructure is confirmed working via the 402 challenge, but consumers should expect to experiment or contact the provider for integration details.
Capabilities
Use cases
- —Querying or creating transactions associated with a specific card resource
- —Integrating pay-per-request card transaction data into agent workflows
- —Testing x402 payment flows on Base with USDC
Fit
Best for
- —Developers experimenting with x402 payment protocols
- —Agents needing on-demand card transaction access without API keys
- —Projects already using USDC on Base
Not for
- —Users needing well-documented, production-grade card processing APIs
- —Anyone requiring detailed request/response schemas before integration
- —High-volume batch processing where per-call pricing is impractical
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/47/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02/request in USDC on Base), but there is no OpenAPI schema, no documentation, no example requests or responses, and the specific endpoint path (/api/v1/cards/47/transactions) is not described anywhere on the site. The docs/pricing/README pages are all empty stubs.
Warnings
- —No documentation available — /docs, /pricing, and /README pages return only a 'Connect wallet' stub with no content
- —This specific endpoint (/api/v1/cards/47/transactions) is not listed among the advertised APIs on the landing page
- —No request or response schema is available; exact functionality is unknown
- —The hardcoded card ID '47' in the path suggests this may be a specific resource rather than a general-purpose API
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/cards/47/transactions
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/cards/47/transactions
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Docs, pricing, and README pages return only 'Connect wallet' with no substantive contenthttps://lowpaymentfee.com/docs