x402-gated premium API access on Base, pay $0.02 per request in USDC — no API keys required.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. It is one of many endpoints offered by the lowpaymentfee.com platform, which hosts a broad catalog of pay-per-call APIs spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, settled in USDC on the Base network, with no API keys, rate limits, or commitments required.
The specific endpoint `/api/v1/cards/33` is listed under the generic label "Premium API Access" and returns `application/json`. The x402 challenge confirms it is live, accepting POST requests, and requires a maximum payment of 20,000 base units of USDC (0x8335…on Base), which equals $0.02 given USDC's 6 decimals. The payment is sent to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` with a 300-second timeout.
Documentation on the site 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 spec, no request/response schema documentation, and no description of what `/api/v1/cards/33` actually returns. The endpoint name "cards" and the numeric ID 33 suggest it may return a specific data card or record, but this is purely speculative. Prospective users should test the endpoint directly to determine its actual functionality.
Capabilities
Use cases
- —Accessing premium data or content behind a per-request USDC paywall
- —Programmatic agent-driven API consumption without pre-registration or API keys
- —Testing x402 payment protocol integrations on Base
Fit
Best for
- —Developers experimenting with x402 pay-per-call patterns
- —Agents that can settle USDC payments on Base automatically
- —Users who want instant API access without signup or subscriptions
Not for
- —Users needing well-documented, production-grade APIs with clear schemas
- —Anyone without a Base-compatible USDC wallet
- —High-volume use cases where per-request pricing may add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/33 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is virtually no documentation: no OpenAPI spec, no request/response schema, no description of what 'cards/33' actually provides. Docs pages are empty. The listing is effectively a stub.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or schema definition for this endpoint; request and response formats are unknown.
- —The purpose of '/api/v1/cards/33' is unclear — 'Premium API Access' is a generic label with no specifics.
- —Cannot verify what data or functionality this endpoint actually provides.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/cards/33
- —All endpoints are priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —The platform offers APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/33