x402-gated card transaction endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a card transactions resource at `/api/v1/cards/42/transactions` via the x402 payment protocol. The endpoint is live and returns a standard 402 challenge requiring payment in USDC on the Base network. The specific resource path suggests it returns or creates transaction data for a particular card (card ID 42), though no detailed documentation or schema for the request/response body is available.
The endpoint charges a maximum of 0.02 USDC per request (20,000 base units with 6 decimals), consistent with the site-wide flat pricing of $0.02/request advertised on the provider's landing page. Payment is settled on-chain via the x402 "exact" scheme to a specified wallet address. The provider advertises no API keys, no rate limits, and instant access across all their endpoints.
The provider (lowpaymentfee.com) hosts a broader suite of x402-gated APIs spanning data analytics, AI/ML inference (sentiment, summarization, classification, embeddings), finance/crypto data feeds, and utility services. However, this specific listing covers only the `/api/v1/cards/42/transactions` endpoint. Documentation pages (/docs, /pricing, /README) returned only a "Connect wallet" prompt with no substantive content, so the exact request format and response schema remain unknown.
Capabilities
Use cases
- —Retrieving or posting transaction data for a specific card via pay-per-call USDC micropayments
- —Integrating card transaction lookups into agent workflows without API key management
- —Programmatic access to card-level transaction records settled on Base L2
Fit
Best for
- —Agents needing on-demand card transaction data without subscription commitments
- —Developers experimenting with x402 payment protocol integrations
- —Low-volume or sporadic access to card transaction endpoints
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —Anyone needing non-USDC or non-Base-network payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/42/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"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 the purpose of this specific cards/transactions resource is unclear. The docs, pricing, and README pages all returned only 'Connect wallet' with no content.
Warnings
- —No request or response schema available — the exact payload format is unknown
- —Documentation pages (/docs, /pricing, /README) are empty beyond a wallet-connect prompt
- —The endpoint path '/api/v1/cards/42/transactions' with a hardcoded card ID 42 is unusual and may be a demo or placeholder
- —The provider's broader API suite is unverified; only this single endpoint was probed
Citations
- —Endpoint returns 402 with x402 challenge requiring USDC on Base network, maxAmountRequired 20000 base unitshttps://lowpaymentfee.com/api/v1/cards/42/transactions
- —Site-wide pricing is $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/cards/42/transactions