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 hosts 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, settled in USDC on the Base network via the x402 protocol.
The specific endpoint at `/api/v1/inbox/90` is listed as "Premium API Access" with a max amount of 20,000 base units of USDC (0.02 USD given 6 decimals). It accepts HTTP POST requests and returns application/json. Payment is made via the x402 exact scheme to the specified wallet address on Base. No API keys or rate limits are advertised — access is gated purely by per-call micropayment.
Documentation is minimal: the landing page lists available endpoints and pricing, but the /api, /pricing, and /README pages all resolve to a wallet-connect prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples. The purpose of the `/api/v1/inbox/90` endpoint specifically is unclear — it does not match any of the named endpoints on the landing page, so its actual functionality is unknown.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data (prices, exchange rates, gas estimates) with per-call payment
- —Running utility operations (geocoding, validation, conversion) on a pay-as-you-go basis
Fit
Best for
- —Agents or applications that need keyless, pay-per-use API access
- —Developers wanting to avoid subscription commitments for occasional API calls
- —Web3-native workflows that can settle USDC micropayments on Base
Not for
- —High-volume use cases where $0.02/request adds up significantly compared to subscription plans
- —Users who need detailed API documentation, SDKs, or guaranteed SLAs
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/90 \
-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 request/response schema, no documentation beyond a landing page listing, and the specific /api/v1/inbox/90 path does not correspond to any named endpoint on the site. Functionality is essentially unknown.
Warnings
- —The /api/v1/inbox/90 endpoint does not match any of the named endpoints listed on the landing page — its actual functionality is unknown.
- —No OpenAPI specification, request schema, or response schema is available.
- —The /api, /pricing, and /README pages all resolve to a wallet-connect prompt with no documentation content.
- —Without documented input/output schemas, callers cannot know what to send or what to expect back.
Citations
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —The x402 challenge for /api/v1/inbox/90 specifies maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base.https://lowpaymentfee.com/api/v1/inbox/90
- —Available endpoint categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure.https://lowpaymentfee.com