x402-gated card-transactions endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com exposes a card-transactions resource at `/api/v1/cards/85/transactions` behind an x402 payment challenge. It is part of a broader platform that offers dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per request and settled in USDC on the Base network.
The specific endpoint probed (`/api/v1/cards/85/transactions`) accepts POST requests and is labeled "Premium API Access" in the x402 challenge. The challenge advertises a maximum amount of 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913, which uses 6 decimals), equating to $0.02 per call. Payment is made via the x402 exact scheme to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
Documentation is extremely sparse. The landing page lists available API paths and pricing but the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawl. The endpoint name suggests it returns transaction data for a specific card (ID 85), but without documentation the exact request body format and response structure are unknown. The platform advertises no API keys, no rate limits, and instant access as selling points.
Capabilities
Use cases
- —Retrieving transaction history for a specific card via a single paid API call
- —Programmatic access to card transaction data without API key registration
- —Agent-driven financial data retrieval with per-request USDC micropayments
Fit
Best for
- —Developers wanting keyless, pay-per-call access to card transaction data
- —AI agents that can settle x402 payments in USDC on Base
- —Prototyping financial data integrations without subscription commitments
Not for
- —Users needing detailed API documentation or request/response schemas before integrating
- —High-volume production workloads where per-request pricing may add up
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/85/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page, and no examples. The purpose of this specific endpoint (cards/85/transactions) is unclear beyond its name.
Warnings
- —No OpenAPI or schema documentation available — request body format and response structure are entirely unknown.
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content.
- —The endpoint path includes a hardcoded card ID (85); it is unclear whether other card IDs are supported or what this resource actually returns.
- —No examples or integration guides found anywhere in the crawl.
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/cards/85/transactions
- —The platform lists all APIs at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Documentation pages (/docs, /api, /pricing, /README) show only 'Connect wallet'https://lowpaymentfee.com/docs