Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad set of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities. Every endpoint is priced at $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no upfront commitments. The specific endpoint probed here (`/api/v1/accounts/100`) is labeled "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) on Base.
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). All endpoints follow the x402 payment protocol — callers receive a 402 challenge with payment details and settle via an `X-PAYMENT` header.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no detailed endpoint documentation available from the crawl. The actual behavior and response format of each endpoint is unknown beyond the x402 challenge metadata.
Capabilities
Use cases
- —Querying real-time financial data (prices, exchange rates, gas estimates) with per-call USDC payments
- —Running AI inference tasks (sentiment analysis, summarization, classification, embeddings) without subscription
- —Accessing utility services (geocoding, validation, conversion) on a pay-as-you-go basis
- —Integrating x402-compatible agent workflows that settle payments automatically on Base
Fit
Best for
- —Agents or developers wanting zero-commitment, per-request API access
- —x402-native workflows that need low-cost micropayments on Base
- —Prototyping across multiple API categories without managing API keys
Not for
- —Production workloads requiring detailed documentation, SLAs, or guaranteed uptime
- —Use cases needing high-throughput bulk access with volume discounts
- —Users who cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/100
# Returns 402 with x402 challenge; attach X-PAYMENT header with signed USDC payment on Base to access.Example
Response
{
"error": "X-PAYMENT header is required",
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3",
"scheme": "exact",
"network": "base",
"mimeType": "application/json",
"resource": "https://lowpaymentfee.com/api/v1/accounts/100",
"description": "Premium API Access",
"maxAmountRequired": "20000",
"maxTimeoutSeconds": 300
}
],
"x402Version": 1
}Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. No OpenAPI schema, no request/response examples, and no details on what the /accounts/100 endpoint actually returns after payment.
Warnings
- —Documentation pages (docs, API, pricing, README) are empty — only show 'Connect wallet'
- —No OpenAPI or schema available; request/response formats are unknown
- —The specific endpoint /api/v1/accounts/100 ('Premium API Access') has no description of what data it returns
- —Cannot verify actual functionality of any endpoint without making a paid request
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limitshttps://lowpaymentfee.com
- —Payment in USDC on Base network via x402 protocolhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units (USDC, 6 decimals = $0.02)https://lowpaymentfee.com/api/v1/accounts/100
- —Platform offers Data & Analytics, AI & ML, Finance & Web3, and Infrastructure API categorieshttps://lowpaymentfee.com
- —Docs, API, pricing, and README pages render only 'Connect wallet'https://lowpaymentfee.com/docs