Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint at /api/v1/payments/332 is labeled "Premium API Access" and accepts POST requests, charging up to 20,000 base units of USDC (i.e., $0.02 given USDC's 6 decimals) per call. No API keys, rate limits, or upfront commitments are required — each request is settled individually via an on-chain micropayment.
The broader platform advertises multiple API categories including 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 listed endpoints share the same $0.02/request pricing. However, the crawled documentation pages (docs, pricing, README) returned only a "Connect wallet" prompt with no further technical detail, so the actual functionality behind each endpoint — including this /api/v1/payments/332 endpoint — is not documented beyond its title.
The x402 challenge is live and well-formed: it specifies the USDC contract on Base (0x8335…), a payTo address, a 300-second timeout, and exact-scheme payment. Because there is no OpenAPI spec, no request/response schema, and no documentation describing what "Premium API Access" actually returns, agents should treat this as a minimally documented endpoint whose concrete behavior is unknown.
Capabilities
Use cases
- —Paying per-call for API access without API keys or subscriptions
- —Demonstrating x402 micropayment protocol integration on Base
- —Agent-driven API consumption with on-chain USDC settlement
Fit
Best for
- —Developers exploring x402 pay-per-request patterns
- —Agents that can settle USDC micropayments on Base
- —Use cases requiring no-signup, no-rate-limit API access
Not for
- —Users needing detailed API documentation or guaranteed SLAs
- —Applications requiring free or fiat-settled endpoints
- —Production workloads that depend on well-documented request/response schemas
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/332 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI spec, no request/response schema, and all documentation pages return only a wallet-connect prompt. The actual functionality of this specific endpoint is undocumented, making it effectively a stub listing.
Warnings
- —No OpenAPI or schema available — request and response formats are unknown.
- —All documentation pages (/docs, /pricing, /README, /api) returned only 'Connect wallet' with no technical content.
- —The purpose of /api/v1/payments/332 ('Premium API Access') is not explained anywhere; it may be a generic or placeholder endpoint.
- —Platform lists many endpoint categories (AI, finance, data) but none have documented behavior.
Citations
- —Endpoint returns HTTP 402 with x402 challenge specifying USDC on Base, maxAmountRequired 20000https://lowpaymentfee.com/api/v1/payments/332
- —All listed endpoints priced at $0.02/request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/payments/332
- —Platform advertises Data & Analytics, AI & ML, Finance & Web3, and Infrastructure API categorieshttps://lowpaymentfee.com