Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that provides a broad catalog of pay-per-request endpoints across 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 utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, paid in USDC on the Base network via the x402 protocol.
The specific endpoint `/api/v1/inbox/81` is listed as "Premium API Access" and its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02. Payment is made per-call with no API keys, no rate limits, and no minimum commitments required. The x402 challenge uses the "exact" scheme with a 300-second timeout.
Note that while the landing page lists many endpoints across multiple categories, the specific function of `/api/v1/inbox/81` is not clearly documented beyond the generic label "Premium API Access." The crawled docs pages (/api, /pricing, /README) all returned only a "Connect wallet" prompt with no additional documentation. Without further documentation or an OpenAPI spec, the exact input/output schema for this endpoint is unknown.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data such as token quotes, gas estimates, and exchange rates on a per-call basis
- —Running data analytics queries and exporting data with per-request billing
- —Using utility services like geocoding, validation, and conversion without subscriptions
Fit
Best for
- —Agents or developers who want instant, keyless API access with crypto micropayments
- —Low-volume or bursty workloads where per-request pricing is more economical than subscriptions
- —Web3-native applications that already hold USDC on Base
Not for
- —High-volume production workloads where bulk pricing or rate guarantees are needed
- —Users who cannot pay in USDC on the Base network
- —Applications requiring detailed SLAs, uptime guarantees, or extensive documentation
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/81 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI spec, no documentation beyond the landing page listing, and the specific purpose of /api/v1/inbox/81 is undocumented. Input/output schemas are unknown.
Warnings
- —The specific function of /api/v1/inbox/81 ('Premium API Access') is not documented; its actual behavior is unknown.
- —No OpenAPI spec or detailed API documentation is available; /api, /pricing, and /README pages all return only a wallet-connect prompt.
- —The broad catalog of endpoints listed on the landing page cannot be independently verified for functionality.
- —Input and output schemas are entirely unknown for this endpoint.
Citations
- —The landing page lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories, all priced at $0.02/request.https://lowpaymentfee.com
- —Pricing is $0.02 per request with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —The x402 challenge for /api/v1/inbox/81 shows maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02.https://lowpaymentfee.com/api/v1/inbox/81