Pay-per-call API key generation on Base via x402 — $0.02 per request in USDC.
What it does
lowpaymentfee.com is a platform offering a suite of pay-per-request APIs settled via the x402 protocol on the Base network using USDC. The specific endpoint at `/api/v1/apikeys/19` is labeled "Premium API Access" and accepts POST requests with an x402 payment challenge. The platform advertises a flat $0.02 per request across all its endpoints, with no API keys, no rate limits, and instant access.
The broader platform lists endpoints spanning four categories: 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 (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per call.
The x402 challenge for this specific endpoint shows a `maxAmountRequired` of 20000 base units of USDC (contract `0x8335...2913` on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the `exact` scheme to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3`. 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 content.
Capabilities
Use cases
- —Purchasing API access keys via micropayment without traditional subscription
- —Programmatic agent-driven API key provisioning using x402 payments
- —Accessing a suite of data, AI, finance, and utility endpoints at $0.02 per call
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto-native micropayments over API key management
Not for
- —Users needing detailed API documentation or OpenAPI specs before purchasing
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/apikeys/19 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, and the landing page confirms pricing and available API categories. However, there is no OpenAPI schema, no request/response examples, and all documentation pages render only 'Connect wallet' with no usable content. The purpose of the specific /apikeys/19 endpoint is unclear beyond its label.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) are all empty — they only show 'Connect wallet'
- —No OpenAPI or schema available; request body format and response structure are unknown
- —The specific function of /api/v1/apikeys/19 ('Premium API Access') is not documented — it is unclear what the response contains or what 'API key' is generated
- —No examples of successful responses are available anywhere in the crawl
Citations
- —Flat pricing of $0.02 per request across all endpointshttps://lowpaymentfee.com
- —No API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/apikeys/19
- —USDC contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/apikeys/19
- —Platform lists endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com