x402-gated premium API access on Base network, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol on the Base network. The specific endpoint `/api/v1/cards/55` is one of many API endpoints offered by the provider, which spans categories including Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure utilities.
The endpoint accepts POST requests and returns JSON responses. Payment is settled in USDC (USD Coin) on Base at a cost of $0.02 per request (20,000 base units with 6 decimals). The x402 challenge confirms the endpoint is live and requires an X-PAYMENT header for access. No API keys or rate limits are advertised — access is purely pay-per-call.
However, the specific functionality of `/api/v1/cards/55` is unclear. The provider's landing page lists various API categories but does not explicitly document a "cards" endpoint. The docs, pricing, and README pages all render only a "Connect wallet" prompt with no additional documentation. Without further information, the exact data or service returned by this particular endpoint cannot be confirmed.
Capabilities
Use cases
- —Accessing premium data or services with per-request USDC micropayments
- —Agent-driven API consumption without API key management
- —Pay-as-you-go access to infrastructure endpoints on Base
Fit
Best for
- —Developers wanting keyless, pay-per-call API access
- —AI agents with x402 payment capability on Base
- —Users who prefer crypto micropayments over subscriptions
Not for
- —Users needing detailed API documentation before purchasing
- —High-volume consumers who need bulk pricing or rate guarantees
- —Anyone without USDC on Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/55 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_token>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02/request in USDC on Base). However, there is no documentation of what `/api/v1/cards/55` actually returns, no OpenAPI schema, no example requests/responses, and the docs pages are empty. The specific purpose of this endpoint is unknown.
Warnings
- —The specific functionality of /api/v1/cards/55 is undocumented — the 'cards' path does not appear in the provider's listed API categories
- —All documentation pages (docs, pricing, README) render only 'Connect wallet' with no content
- —No OpenAPI spec or response schema available
Citations
- —Endpoint returns 402 with x402 challenge requiring USDC payment on Base networkhttps://lowpaymentfee.com/api/v1/cards/55
- —Provider advertises $0.02 per request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/55