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/93` is listed as "Premium API Access" and requires a POST request with an x402 payment header. The x402 challenge confirms the endpoint is live, accepting payments of up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per request (USDC uses 6 decimals).
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 $0.02 per request with no API keys, no rate limits, and no minimum commitments required.
However, the specific endpoint probed (`/api/v1/carts/93`) does not clearly map to any of the advertised API categories — it appears to be a cart resource, which is not documented on the landing page. Documentation pages (/docs, /api, /pricing, /README) all returned only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no detailed documentation available for any endpoint, making it difficult to determine what this specific cart endpoint actually returns.
Capabilities
Use cases
- —Paying per-request for API access without needing API keys or subscriptions
- —Integrating x402-compatible agents with a low-cost endpoint for testing micropayment flows
- —Accessing miscellaneous data/AI/finance/utility endpoints via crypto micropayments
Fit
Best for
- —Developers experimenting with x402 protocol micropayments
- —Agents that need keyless, pay-per-call API access on Base
- —Low-volume consumers who want no-commitment API usage
Not for
- —Production workloads requiring documented, well-specified API contracts
- —Users who need detailed request/response schemas before integration
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/carts/93 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <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 request/response examples, and the specific /api/v1/carts/93 path is not explained anywhere on the site. All doc pages return only 'Connect wallet' with no content.
Warnings
- —The endpoint path /api/v1/carts/93 does not match any of the advertised API categories on the landing page — its actual functionality is unknown.
- —No documentation is available: /docs, /api, /pricing, and /README all return only a 'Connect wallet' prompt with no substantive content.
- —No OpenAPI schema, request format, or response examples are provided anywhere.
- —The platform's advertised API categories (AI, analytics, finance, utilities) are unverifiable since no docs exist.
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913), equaling $0.02 per request.https://lowpaymentfee.com/api/v1/carts/93
- —The landing page lists APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories, all priced at $0.02/request.https://lowpaymentfee.com
- —The site advertises no API keys, no rate limits, instant access, and Base network settlement.https://lowpaymentfee.com
- —Documentation pages (/docs, /api, /pricing, /README) returned only 'Connect wallet' with no substantive content.https://lowpaymentfee.com/docs