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-enabled API platform that exposes a collection of endpoints across four categories: 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 priced at $0.02 per request and settle in USDC on the Base network.
The specific endpoint at `/api/v1/carts/87` is listed as "Premium API Access" and returns a valid x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base, 6 decimals), which equals $0.02. Payment is made via the x402 exact scheme — no API keys, subscriptions, or rate limits are advertised. The endpoint accepts POST requests and returns application/json.
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 what the `/api/v1/carts/87` endpoint actually returns or what input it expects. The platform appears to be a demonstration or early-stage x402 marketplace rather than a mature, well-documented API provider.
Capabilities
Use cases
- —Paying per-call for lightweight API access without managing API keys or subscriptions
- —Integrating x402-compatible agents with a low-cost endpoint for testing payment flows
- —Accessing data, AI, finance, or utility services via crypto micropayments
Fit
Best for
- —Developers experimenting with x402 payment protocol integrations
- —Agents that need keyless, pay-per-request API access on Base
- —Low-volume or sporadic API consumers who want no commitments
Not for
- —Production workloads requiring detailed API documentation and SLAs
- —Users who need non-crypto (fiat) payment methods
- —High-throughput applications where per-request crypto settlement adds latency
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/carts/87 \
-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 no OpenAPI schema, no request/response examples, and all documentation pages are empty beyond a wallet-connect prompt. The purpose of the specific /api/v1/carts/87 endpoint is unclear. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —All doc/pricing/API pages render only 'Connect wallet' with no usable content
- —The specific endpoint /api/v1/carts/87 ('Premium API Access') does not appear in the site's listed API catalog — its purpose is unknown
- —No request body schema or response examples are available anywhere
Citations
- —All listed endpoints are priced at $0.02 per request with no minimums or commitmentshttps://lowpaymentfee.com
- —Endpoints settle in USDC on the Base network with no API keys or rate limitshttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/carts/87 specifies maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913)https://lowpaymentfee.com/api/v1/carts/87
- —Categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com