Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad set of endpoints across data analytics, AI/ML inference, finance/Web3 data, and utility services. Every endpoint costs $0.02 per request, paid in USDC on the Base network via the x402 payment protocol. There are no API keys, no rate limits, and no upfront commitments — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/payments/392` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment scheme is "exact" with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.
The 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 (geocoding, validation, conversion, generation). However, documentation pages beyond the landing page returned only a "Connect wallet" prompt with no actual API docs, request/response schemas, or usage examples. Without documentation it is unclear what specific inputs this particular endpoint expects or what it returns.
Capabilities
Use cases
- —Accessing analytics metrics and reports without managing API keys
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) with per-call crypto payments
- —Fetching real-time crypto prices, gas estimates, and exchange rates
- —Geocoding and data conversion utilities paid per request
Fit
Best for
- —Developers who want zero-friction API access without signup or key management
- —Agents and bots that can settle payments programmatically via x402 on Base
- —Low-volume or sporadic API consumers who prefer pay-as-you-go pricing
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed API documentation, SLAs, or guaranteed uptime
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/392 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI schema, no documentation beyond the landing page, no request/response examples, and the specific purpose of the '/api/v1/payments/392' endpoint labeled 'Premium API Access' is unclear. The docs, pricing, and README pages all returned only 'Connect wallet' with no content.
Warnings
- —No API documentation available — all doc pages return only 'Connect wallet' with no content
- —No request or response schema provided for this endpoint
- —The purpose of '/api/v1/payments/392' ('Premium API Access') is ambiguous — it does not match any of the named endpoints on the landing page
- —Cannot verify what data or service this specific endpoint actually provides
Citations
- —The endpoint returns a 402 challenge requesting 20,000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/payments/392
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/payments/392