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/67/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, settled to a specified wallet address. The endpoint accepts HTTP POST requests and returns JSON.
The broader lowpaymentfee.com platform advertises a suite of pay-per-request APIs spanning data & analytics, AI/ML (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 with no API keys, no rate limits, and no commitments required — payment is handled entirely via the x402 protocol using USDC on Base.
However, the specific endpoint being listed here (`/api/v1/cards/67/transactions`) does not appear in the site's publicly documented API catalog. Its purpose — whether it relates to virtual card management, transaction history, or something else — is not documented in the crawled material. The docs, pricing, and API pages all returned only a "Connect wallet" prompt with no further content. Without documentation or schema details for this particular resource, its exact functionality remains 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-level transaction data settled in USDC on Base
Fit
Best for
- —Agents that need on-demand card transaction access without subscription commitments
- —Developers wanting crypto-native pay-per-request billing on Base
- —Workflows requiring no-signup, keyless API access
Not for
- —Use cases requiring detailed API documentation or guaranteed SLAs
- —High-volume batch processing where per-request pricing is inefficient
- —Users who need fiat-only payment rails
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/67/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but the specific /cards/67/transactions resource is undocumented. No request/response schema, no docs content beyond 'Connect wallet', and no examples are available. The endpoint's actual functionality is unknown.
Warnings
- —The /api/v1/cards/67/transactions endpoint is not listed in the site's public API catalog — its purpose is undocumented.
- —All docs, pricing, and API pages returned only 'Connect wallet' with no substantive content.
- —No request body schema or response schema is available for this endpoint.
- —The resource path includes a hardcoded ID (67), suggesting it may be instance-specific rather than a general-purpose API.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USD) on Base networkhttps://lowpaymentfee.com/api/v1/cards/67/transactions
- —The site advertises $0.02 per request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/67/transactions
- —The site lists APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com