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/81/transactions`. It is part of a broader platform offering data & analytics, AI/ML inference, finance/Web3, and infrastructure utility endpoints — 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/81/transactions` is labeled "Premium API Access" in the x402 challenge. The x402 challenge confirms the endpoint is live (HTTP 402 returned), accepts the `exact` payment scheme, and targets USDC at contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913` on Base. The maximum amount required is 20,000 base units, which at 6 decimals equals $0.02. The payment timeout is 300 seconds.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description of what the card transactions endpoint actually returns or what input it expects. The endpoint path suggests it relates to financial card transaction data for card ID 81, but this is speculative. Prospective users should be aware that without documentation, the actual behavior and data format of this endpoint are unknown.
Capabilities
Use cases
- —Retrieving card transaction data via a pay-per-request model
- —Integrating x402-gated financial endpoints into agent workflows
- —Accessing card-level transaction records without API key management
Fit
Best for
- —Developers experimenting with x402 payment protocol integrations
- —Agents that need on-demand card transaction data with no subscription
- —Projects already operating on Base with USDC liquidity
Not for
- —Production use cases requiring documented request/response schemas
- —Users who need free or fiat-settled API access
- —High-volume batch processing where per-call costs add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/81/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is zero documentation on what the endpoint accepts or returns. No OpenAPI schema, no examples, and the docs/pricing/README pages are all empty wallet-connect stubs. The purpose of 'cards/81/transactions' is unclear.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or request/response schema provided; input and output formats are completely unknown.
- —The specific purpose of '/api/v1/cards/81/transactions' (card ID 81) is undocumented and unclear.
- —The broader platform lists many endpoints (AI, analytics, finance, utils) but none have documented schemas.
Citations
- —The endpoint returns HTTP 402 with x402 challenge, confirming it is live on Base network with USDC payment.https://lowpaymentfee.com/api/v1/cards/81/transactions
- —maxAmountRequired is 20000 base units of USDC (6 decimals) = $0.02 per request.https://lowpaymentfee.com/api/v1/cards/81/transactions
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —Docs, API, pricing, and README pages render only a 'Connect wallet' prompt with no further content.https://lowpaymentfee.com/docs