x402-gated card-transactions endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com exposes a card transactions resource at `/api/v1/cards/2/transactions` behind the x402 payment protocol. It is one of many endpoints offered by the lowpaymentfee.com platform, which advertises a flat $0.02-per-request pricing model with no API keys, no rate limits, and instant access. Payment is settled in USDC on the Base network.
The x402 challenge confirms the endpoint is live and accepts POST requests. The maximum amount required is 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment scheme is "exact" with a 300-second timeout. No OpenAPI schema, detailed documentation, or example request/response bodies were found in the crawl — the docs, pricing, API, and README pages all returned only a "Connect wallet" prompt with no substantive content.
The broader lowpaymentfee.com platform lists endpoints across data & analytics, AI & ML (sentiment, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). However, the specific functionality of the `/api/v1/cards/2/transactions` endpoint is not documented on the landing page, and its purpose (card transaction data, card transaction creation, etc.) can only be inferred from the URL path. Without request/response schemas or documentation, the exact capabilities remain unclear.
Capabilities
Use cases
- —Retrieving or creating card transaction records via a pay-per-call model
- —Integrating card transaction data into agent workflows without API key management
- —Programmatic access to card transaction information settled in USDC on Base
Fit
Best for
- —Developers wanting keyless, pay-per-request card transaction access
- —AI agents that can settle x402 payments in USDC on Base
- —Prototyping integrations that need card transaction data without subscription commitments
Not for
- —Production use cases requiring well-documented request/response schemas
- —High-volume workloads where per-request pricing may add up
- —Users who need fiat-only payment rails
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/2/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is no documentation, no request/response schema, and the specific purpose of this card-transactions endpoint is undocumented. The crawled docs/pricing/API pages are all empty beyond a wallet-connect prompt.
Warnings
- —No request or response schema available — the exact functionality of /api/v1/cards/2/transactions is unknown
- —All documentation pages (docs, pricing, API, README) returned only 'Connect wallet' with no content
- —The /api/v1/cards/2/transactions path is not listed among the endpoints on the landing page, making its purpose unclear
- —No examples or error codes documented
Citations
- —Flat $0.02 per request pricing with no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/cards/2/transactions
- —Payment scheme is 'exact' with maxTimeoutSeconds of 300https://lowpaymentfee.com/api/v1/cards/2/transactions