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/34` is listed as "Premium API Access" and accepts POST requests. The x402 challenge advertises a max amount of 20,000 base units of USDC (0x8335…), which equals $0.02 per request (USDC uses 6 decimals). Payment is made via the x402 exact scheme with no API keys, rate limits, or subscriptions required.
The broader platform advertises four categories of endpoints: 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.
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/34` ("Premium API Access") is unclear and cannot be determined from available material. The endpoint is live and returns a valid 402 challenge, but without documentation it is difficult to know what data or service it actually provides.
Capabilities
Use cases
- —Paying per-request for API access without subscriptions or API keys
- —Integrating x402-compatible agents with low-cost utility endpoints
- —Accessing data, AI, or finance endpoints via crypto micropayments
Fit
Best for
- —Developers wanting zero-commitment pay-per-use API access
- —x402-compatible AI agents needing cheap utility endpoints
- —Projects already operating on the Base L2 network
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where per-request pricing may add up versus flat-rate plans
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/34 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC payments on Base at $0.02/request. However, there is no OpenAPI schema, no request/response examples, and all documentation pages are empty beyond a wallet-connect prompt. The specific purpose of /api/v1/cards/34 is undocumented and unclear.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —The specific functionality of /api/v1/cards/34 ('Premium API Access') is completely undocumented; its purpose is unknown.
- —No OpenAPI schema or request/response examples are provided for any endpoint.
- —No robots.txt or agents.txt found on the domain.
Citations
- —The endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/cards/34
- —All endpoints are priced at $0.02/request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/cards/34