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 collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and general utility services. All endpoints are paid per-request using USDC on the Base network via the x402 protocol — no API keys, no rate limits, and no subscriptions required.
The specific endpoint at `/api/v1/keys/18` is listed as "Premium API Access" and costs up to $0.02 per call (maxAmountRequired of 20,000 base units of USDC with 6 decimals). The platform advertises sibling endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — all at the same $0.02 price point.
The platform's landing page confirms a simple pay-per-use model with no minimums or commitments. Payment is settled on-chain to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) on Base. The x402 challenge was successfully captured, confirming the endpoint is live. However, documentation is extremely sparse — there is no OpenAPI spec, no request/response schema, and no examples available. The exact functionality behind the "Premium API Access" label at `/api/v1/keys/18` is unclear and may differ from the other listed endpoints.
Capabilities
Use cases
- —Agents that need on-demand AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Fetching real-time crypto token quotes, gas estimates, or exchange rates with per-call payment
- —Geocoding or data validation as a utility service paid in USDC on Base
- —Exporting analytics data or generating reports on a pay-as-you-go basis
Fit
Best for
- —AI agents needing keyless, pay-per-call access to diverse API endpoints
- —Developers who prefer crypto micropayments over subscription billing
- —Applications on Base that want native USDC settlement for API calls
Not for
- —High-volume use cases where per-call pricing at $0.02 adds up quickly compared to bulk plans
- —Users who need detailed API documentation, schemas, or SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/18 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation, and no examples. The specific purpose of the `/api/v1/keys/18` endpoint labeled "Premium API Access" is ambiguous — it does not appear in the site's listed endpoint catalog, making it unclear what it actually returns.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The endpoint /api/v1/keys/18 ('Premium API Access') is not listed among the site's advertised API catalog — its exact functionality is unknown
- —No request or response examples are available; integration requires trial-and-error
- —Pricing and /README pages returned only 'Connect wallet' with no useful content
Citations
- —The platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories, all at $0.02/requesthttps://lowpaymentfee.com
- —Pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/keys/18