x402-gated API platform on Base offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402 protocol API marketplace that gates access to a variety of endpoints behind per-request micropayments settled in USDC on the Base network. The specific endpoint at `/api/v1/cards/35` is listed as "Premium API Access" and costs up to $0.02 per call (maxAmountRequired of 20,000 base units of USDC, which has 6 decimals = $0.02). Payment is handled via the x402 exact scheme — callers attach an X-PAYMENT header with a signed payment to the payTo address, and the endpoint returns JSON.
The broader platform advertises four categories of APIs: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at the same $0.02/request price point. The platform emphasizes no API keys, no rate limits, no minimums, and instant access.
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 detailed documentation for any endpoint. The specific functionality behind `/api/v1/cards/35` ("Premium API Access") is not described beyond its title, so its actual behavior is unknown.
Capabilities
Use cases
- —Paying per-request for API access without needing API keys or subscriptions
- —Accessing data, AI, finance, or utility endpoints via x402 micropayments
- —Integrating agent-purchasable API calls settled on Base L2
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously on Base
- —Projects needing low-cost per-call API access without signup
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where per-request pricing may not be cost-effective
- —Users without a Base-compatible wallet or USDC holdings
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/35 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is zero documentation on what /api/v1/cards/35 actually returns, no OpenAPI schema, no request/response examples, and all doc pages render only 'Connect wallet'. The actual functionality is unknown.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format for /api/v1/cards/35
- —The purpose of the 'Premium API Access' endpoint at /api/v1/cards/35 is completely undocumented
- —Cannot verify what data or service this specific endpoint provides
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/cards/35
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers APIs in Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/cards/35