x402-gated card-transactions endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com exposes a POST-based card transactions API at `/api/v1/cards/93/transactions`. It is part of a broader platform offering data & analytics, AI/ML inference, finance/Web3, and infrastructure utility APIs — all gated behind the x402 payment protocol on the Base network. Each request costs $0.02 in USDC (USD Coin), settled on-chain with no API keys, no rate limits, and no upfront commitments.
The specific endpoint `/api/v1/cards/93/transactions` is labeled "Premium API Access" in the x402 challenge. The x402 challenge confirms it accepts an exact payment scheme with a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals), which equals $0.02. The endpoint accepts POST requests and returns `application/json`. Beyond the generic label and the card/transactions URL path, no detailed documentation, request schema, or response schema is available — the docs, pricing, and README pages all resolve to a minimal "Connect wallet" prompt with no substantive content.
Because the endpoint path references "cards/93/transactions," it likely relates to financial card transaction data or operations, but the exact input parameters and response structure are undocumented. The platform advertises instant access and payment via the Base L2 network. The endpoint is confirmed live (402 challenge captured successfully).
Capabilities
Use cases
- —Querying card transaction data on a per-request payment basis
- —Integrating card transaction lookups into agent workflows without API key management
- —Paying for financial data access with on-chain USDC micropayments
Fit
Best for
- —Agents needing card transaction data without subscription commitments
- —Developers who prefer crypto-native pay-per-call pricing
- —Low-volume or sporadic access to card transaction information
Not for
- —High-volume production workloads requiring documented SLAs and schemas
- —Users who need detailed API documentation and response guarantees before integration
- —Non-crypto users who cannot settle payments in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/93/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is live and the x402 challenge is well-formed with clear pricing ($0.02 USDC on Base). However, there is no documentation, no request/response schema, no examples, and the endpoint's actual functionality ("Premium API Access" on a cards/transactions path) is opaque. Docs pages return only a wallet-connect prompt.
Warnings
- —No request or response schema is documented; input parameters are unknown.
- —The endpoint description is a generic 'Premium API Access' label — actual functionality is unclear.
- —All documentation pages (/docs, /pricing, /README, /api) return only a 'Connect wallet' stub with no content.
- —The specific resource 'cards/93' suggests a hardcoded card ID; generalizability is unknown.
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC (6 decimals) = $0.02 per requesthttps://lowpaymentfee.com/api/v1/cards/93/transactions
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/93/transactions
- —Platform advertises $0.02/request, no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —Docs, pricing, README, and API pages resolve to minimal 'Connect wallet' contenthttps://lowpaymentfee.com/docs