Pay-per-call API platform on Base via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across data analytics, AI/ML inference, finance/Web3, and utility services. All endpoints are priced at $0.02 per request, paid in USDC on the Base network. The x402 protocol eliminates the need for API keys, accounts, or subscriptions — callers simply attach a payment header to each request.
The specific endpoint at `/api/v1/payments/338` is labeled "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USDC, i.e., $0.02) on Base. The payment scheme is "exact" with a 300-second timeout. The platform advertises no rate limits and instant access.
The broader platform lists endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation. However, documentation pages (docs, pricing, README) all returned only a "Connect wallet" prompt with no substantive content, so the actual behavior and response formats of these endpoints are undocumented in the crawled material. The endpoint's outputSchema indicates it accepts HTTP POST requests and is discoverable.
Capabilities
Use cases
- —Agents that need on-demand AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Fetching real-time crypto token quotes and gas estimates with per-call payment
- —Geocoding or data validation as a utility service within automated workflows
- —Exporting analytics data or generating reports on a pay-as-you-go basis
- —Web3-native applications that want to pay for API access directly in USDC on Base
Fit
Best for
- —AI agents and bots that need keyless, pay-per-call API access
- —Developers prototyping with low-cost, no-commitment API endpoints
- —Web3-native workflows that settle payments on Base in USDC
Not for
- —High-volume production workloads where per-call pricing at $0.02 adds up quickly
- —Users who need detailed API documentation, SDKs, or guaranteed SLAs
- —Applications requiring non-USDC or non-Base payment rails
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/338 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Example
Request
{
"url": "https://lowpaymentfee.com/api/v1/payments/338",
"body": {},
"method": "POST",
"headers": {
"X-PAYMENT": "<x402-payment-header>",
"Content-Type": "application/json"
}
}Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, all documentation pages returned only 'Connect wallet' with no actual content — there is no OpenAPI schema, no response examples, and no description of what this specific 'Premium API Access' endpoint actually returns. The platform lists many endpoints but provides no technical documentation for any of them.
Warnings
- —All documentation pages (/docs, /pricing, /README, /api) returned only 'Connect wallet' with no substantive content
- —No OpenAPI or schema documentation available for any endpoint
- —The specific behavior and response format of /api/v1/payments/338 ('Premium API Access') is completely undocumented — it is unclear what it does beyond the generic label
- —The broad catalog of endpoints (AI, finance, utils) is advertised but none have documented request/response schemas
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0.02 USDC) on Base with 300-second timeouthttps://lowpaymentfee.com/api/v1/payments/338
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com