Pay-per-request API suite on Base via x402 — data, AI, finance, and utility endpoints at $0.02/call.
What it does
lowpaymentfee.com offers a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. The specific endpoint `/api/v1/carts/36` is listed as "Premium API Access" and requires a payment of up to 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals = $0.02) per call. No API keys or rate limits are advertised; callers pay per request using USDC on Base.
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 are listed at the same $0.02/request price point.
The `/api/v1/carts/36` endpoint specifically accepts HTTP POST requests and returns `application/json`. Beyond the x402 challenge metadata, no OpenAPI schema, request body documentation, or response examples are available. The docs, pricing, and API pages behind the site all appear to require a wallet connection and provide no additional textual documentation. The exact functionality behind "Premium API Access" on the carts/36 path is unclear — it does not map obviously to any of the named API categories on the landing page.
Capabilities
Use cases
- —Accessing premium API data without managing API keys or subscriptions
- —Making one-off paid API calls settled in USDC on Base
- —Agent-driven workflows that need instant, keyless API access
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously on Base
- —Users who prefer crypto micropayments over traditional billing
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/carts/36 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response documentation, and the purpose of the specific /api/v1/carts/36 path is undefined beyond the generic label 'Premium API Access'. Docs pages all resolve to a wallet-connect prompt with no content.
Warnings
- —No OpenAPI or request/response schema available — the exact functionality of /api/v1/carts/36 is unknown
- —All documentation pages (docs, pricing, API, README) render only a 'Connect wallet' prompt with no usable content
- —The endpoint path '/api/v1/carts/36' does not correspond to any of the named API categories on the landing page; its purpose is unclear
Citations
- —The endpoint returns a 402 x402 challenge requiring up to 20,000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/carts/36
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/carts/36
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers Data & Analytics, AI & ML, Finance & Web3, and Infrastructure endpoint categorieshttps://lowpaymentfee.com