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/46/transactions` behind the x402 payment protocol. When called without payment, it returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USD) on the Base network. The payment is settled on-chain to a specified wallet address using the "exact" scheme.
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 data (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at $0.02 per request with no API keys, no rate limits, and no commitments required — payment is handled entirely via the x402 protocol on the Base L2 network.
However, the specific endpoint being listed here (`/api/v1/cards/46/transactions`) is not documented on the site's landing page among the advertised APIs. Its purpose — likely related to card transaction data — can only be inferred from the URL path. No request/response schema, documentation, or examples are available for this particular endpoint. The docs, pricing, and API pages behind the site all appear to require a wallet connection and provide no additional content.
Capabilities
Use cases
- —Retrieving card transaction data via a single paid API call
- —Integrating pay-per-request card transaction lookups into agent workflows
- —Programmatic access to card-level transaction records without API key management
Fit
Best for
- —Agents or services needing on-demand card transaction data with crypto micropayments
- —Developers experimenting with x402 protocol integrations on Base
- —Use cases where no-signup, pay-per-call access is preferred
Not for
- —Production workloads requiring documented request/response schemas and SLAs
- —Users who need fiat-only payment options (this endpoint requires USDC on Base)
- —High-volume batch processing where per-request pricing may not be economical
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/46/transactions
# Returns 402 with x402 challenge; attach X-PAYMENT header with valid USDC payment to proceed.Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge), but there is no documentation, no request/response schema, and the specific card-transactions endpoint is not listed among the site's advertised APIs. The docs/pricing/API pages are empty beyond a wallet-connect prompt. Effectively a stub listing.
Warnings
- —The endpoint /api/v1/cards/46/transactions is not listed among the site's publicly advertised APIs — its purpose is inferred solely from the URL path.
- —No request body schema or response schema is available for this endpoint.
- —Documentation pages (docs, pricing, API, README) returned no useful content beyond a wallet-connect prompt.
- —The nature of 'card 46 transactions' is unclear — it could be test/demo data or a specific resource that may not persist.
Citations
- —The x402 challenge requests up to 20,000 base units of USDC (asset 0x8335…) on Base network with the exact scheme.https://lowpaymentfee.com/api/v1/cards/46/transactions
- —The site advertises all endpoints at $0.02 per request with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —The site lists APIs across data/analytics, AI/ML, finance/Web3, and infrastructure categories but does not list /api/v1/cards/46/transactions.https://lowpaymentfee.com