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/68/transactions` behind the x402 payment protocol. When called without payment, it returns a 402 challenge advertising USDC payment on the Base network. The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02 USD per request.
The broader lowpaymentfee.com platform advertises a suite of pay-per-request APIs spanning data & analytics, AI & machine learning (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at $0.02 per request, settled in USDC on Base, with no API keys, no rate limits, and no minimum commitments.
However, this specific endpoint (`/api/v1/cards/68/transactions`) is not listed among the publicly documented APIs on the landing page, and no documentation, request schema, or response schema is available for it. The endpoint is live and returns a valid x402 challenge via POST, but without further docs it is unclear what data it returns or what request body it expects. The provider's docs, pricing, and API pages all render only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Retrieving transaction data for a specific card via pay-per-call USDC micropayment
- —Programmatic access to card transaction records without traditional API key registration
- —Agent-driven financial data retrieval settled on Base L2
Fit
Best for
- —Developers wanting keyless, pay-per-use card transaction data
- —AI agents that can settle x402 USDC payments on Base
- —Prototyping micropayment-gated financial APIs
Not for
- —Users needing detailed API documentation or guaranteed SLAs before integrating
- —High-volume batch processing where per-request pricing may add up
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/68/transactions
# Returns 402 with x402 challenge; attach X-PAYMENT header with USDC payment proof on Base to access.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no request/response schema, and this specific path is not listed among the provider's advertised APIs. The docs pages are empty beyond a wallet-connect prompt. Effectively a stub listing.
Warnings
- —This specific endpoint (/api/v1/cards/68/transactions) is not listed among the provider's publicly documented APIs
- —No request body schema or response schema is available
- —All documentation pages (docs, api, pricing, README) render only a 'Connect wallet' prompt with no usable content
- —The purpose and data returned by this endpoint are unknown
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/cards/68/transactions
- —USDC asset contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/cards/68/transactions
- —All listed APIs priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Provider advertises APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com