Pay-per-call API suite on Base via x402 — data, AI, finance, and utility endpoints at $0.02/request.
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 at `/api/v1/transactions/4` is labeled "Premium API Access" and accepts POST requests, settling payments in USDC (contract 0x8335…2913 on Base). The x402 challenge indicates a maximum amount of 20,000 base units, which at 6 decimals for USDC equals $0.02 per request.
The provider's landing page 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.
Documentation beyond the landing page is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional technical detail. There is no OpenAPI schema, no request/response examples, and no description of what the `/api/v1/transactions/4` endpoint specifically returns. The exact purpose of this particular endpoint (as opposed to the named endpoints on the homepage) is unclear.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data such as token quotes, gas estimates, and exchange rates on a per-call basis
- —Running utility operations like geocoding, validation, and data conversion with instant crypto-settled payments
- —Integrating pay-as-you-go data analytics into agent workflows
Fit
Best for
- —Developers wanting zero-signup, pay-per-request API access
- —AI agents that can settle x402 payments in USDC on Base
- —Projects needing low-cost micropayment-gated endpoints without rate limits
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —Applications requiring high-volume bulk pricing or subscription plans
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/4 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response examples, and no documentation beyond a landing page listing. The specific purpose of /api/v1/transactions/4 is undocumented. Docs pages return only 'Connect wallet' with no content.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The specific endpoint /api/v1/transactions/4 is not listed among the named APIs on the homepage — its exact function is unknown
- —All documentation pages (docs, API, pricing, README) render only 'Connect wallet' with no usable content
- —No request or response examples are available anywhere in the crawled material
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units in USDC (6 decimals) = $0.02 on Base networkhttps://lowpaymentfee.com/api/v1/transactions/4
- —The landing page lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories all at $0.02/requesthttps://lowpaymentfee.com
- —The site advertises no API keys, no rate limits, instant access, and Base network settlementhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transactions/4