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/75` is listed as "Premium API Access" and requires a payment of up to 20,000 base units of USDC (i.e., $0.02 given USDC's 6 decimals) per call. Payment is made via the x402 exact scheme with no API keys, rate limits, or subscriptions required.
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 per request price point. The platform accepts POST requests and returns JSON responses.
Note that the specific `/api/v1/carts/75` endpoint's purpose is unclear — its description is simply "Premium API Access" with no further documentation. The docs, API, pricing, and README pages 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 from the crawl. The endpoint is confirmed live (returns a valid 402 challenge), but what data or functionality it actually provides is unknown.
Capabilities
Use cases
- —Accessing pay-per-use API endpoints without subscriptions or API keys
- —Making micropayment-gated API calls settled on Base L2 in USDC
- —Agent-driven programmatic access to gated resources via x402 protocol
Fit
Best for
- —Developers wanting zero-commitment, pay-per-call API access
- —AI agents that can settle x402 payments autonomously on Base
- —Users who prefer crypto micropayments over traditional API billing
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —Applications requiring guaranteed SLAs or enterprise support
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/carts/75 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no documentation, no OpenAPI schema, no request/response examples, and the actual functionality of /api/v1/carts/75 is completely undocumented. All secondary pages returned only 'Connect wallet' with no content.
Warnings
- —No documentation available — docs, API, pricing, and README pages all return only 'Connect wallet' with no content
- —The specific endpoint /api/v1/carts/75 has no description beyond 'Premium API Access'; its actual functionality is unknown
- —No OpenAPI schema or request/response examples are provided
- —This endpoint path (/api/v1/carts/75) does not appear in the site's own listed API catalog, making its purpose unclear
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/carts/75
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/carts/75
- —All listed APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers Data & Analytics, AI & ML, Finance & Web3, and Infrastructure API categorieshttps://lowpaymentfee.com