x402-gated card-transaction endpoint on Base, paying $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com exposes a card-transactions resource at `/api/v1/cards/52/transactions` behind the x402 payment protocol. When called without payment, it returns a 402 challenge requesting USDC on the Base network. The price per request is $0.02 (20,000 base units of USDC with 6 decimals). Payment is settled on-chain to the specified wallet address using the "exact" scheme, with a maximum timeout of 300 seconds.
The provider's landing page advertises a broad suite of 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 at the same $0.02/request price point with no API keys, no rate limits, and instant access via x402 on Base.
However, the specific endpoint being listed here (`/api/v1/cards/52/transactions`) is labeled only as "Premium API Access" with no further documentation about its request schema, expected input fields, or response format. The docs, pricing, API, and README pages all returned only a "Connect wallet" prompt with no substantive content. Without documentation or example payloads, the exact functionality of this card-transactions endpoint remains unclear — it could relate to financial card transaction data, but this is speculative.
Capabilities
Use cases
- —Retrieving transaction data for a specific card via a pay-per-request model
- —Integrating on-chain micropayments into agent workflows that need card transaction info
- —Accessing financial data without traditional API key provisioning
Fit
Best for
- —Agents that can settle x402 payments in USDC on Base
- —Use cases requiring keyless, pay-per-call access to card transaction data
- —Developers exploring x402 protocol integrations
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume batch processing where per-request fees add up quickly
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/52/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no request/response schema, and no explanation of what the card-transactions endpoint actually returns. The docs pages are empty. This is effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, API, and README pages all return only 'Connect wallet' with no content.
- —The specific purpose of /api/v1/cards/52/transactions is undocumented; 'Premium API Access' is the only description provided.
- —No request or response schema is available; callers cannot know what fields to send or expect back.
- —The endpoint path references a hardcoded card ID (52), which may indicate a demo or placeholder resource.
Citations
- —The endpoint returns a 402 challenge requesting 20,000 base units of USDC on Base network with the exact schemehttps://lowpaymentfee.com/api/v1/cards/52/transactions
- —The provider advertises $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/52/transactions
- —Docs, pricing, API, and README pages return only 'Connect wallet' with no substantive contenthttps://lowpaymentfee.com/docs