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/carts/7` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). 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 priced at $0.02 per request with no API keys, no rate limits, and no minimum commitments.
Note that the specific functionality behind `/api/v1/carts/7` is not documented beyond the label "Premium API Access." The docs, pricing, and API pages all render only a "Connect wallet" prompt with no additional technical documentation or schema details. Without sending a paid request, the actual response payload and behavior of this endpoint remain unknown.
Capabilities
Use cases
- —Agents that need on-demand API access without pre-registration or API keys
- —Micropayment-gated data retrieval where per-call billing is preferred over subscriptions
- —Testing x402 protocol integrations with a live, low-cost endpoint
Fit
Best for
- —Developers exploring x402 payment protocol on Base
- —AI agents needing keyless, pay-per-use API access
- —Low-volume consumers who want no subscription commitment
Not for
- —High-volume production workloads where per-request payment overhead is impractical
- —Users who need detailed API documentation or guaranteed SLAs before purchasing
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/carts/7 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI schema, no example request/response, and the actual functionality behind /api/v1/carts/7 is completely opaque. The docs/pricing/API pages all render only a wallet-connect prompt with no useful content.
Warnings
- —The specific functionality of /api/v1/carts/7 ('Premium API Access') is undocumented — the actual response payload is unknown without making a paid request.
- —All documentation pages (docs, pricing, API, README) render only a 'Connect wallet' prompt with no technical content.
- —No OpenAPI spec, no request/response schema, and no usage examples are available.
- —The platform lists many endpoints across categories but none have detailed documentation visible from the crawl.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913).https://lowpaymentfee.com/api/v1/carts/7
- —All endpoints are priced at $0.02/request with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categories.https://lowpaymentfee.com