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 variety of 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 with no API keys, no rate limits, and no commitments required. The x402 protocol handles payment inline: callers attach an X-PAYMENT header with a signed USDC payment, and the server fulfills the request upon verification.
The specific endpoint at `/api/v1/charges/111` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base. The platform advertises additional endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, conversion, and data export — all at the same $0.02 price point.
Documentation is extremely sparse. The /docs, /pricing, /api, 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 description of what the `/api/v1/charges/111` endpoint actually returns. The landing page lists endpoint names and prices but provides no detail on input parameters or response formats. Prospective users should be aware that without documentation, the actual behavior of each endpoint is unknown.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without API key signup
- —Fetching real-time crypto/finance data with per-request USDC micropayments
- —Using utility endpoints (geocoding, validation, conversion) on a pay-as-you-go basis
- —Integrating agent-purchasable API calls into autonomous workflows via x402
Fit
Best for
- —Developers wanting zero-signup, pay-per-use API access
- —AI agents that can settle x402 payments autonomously on Base
- —Projects needing low-cost micropayment-gated endpoints
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Applications requiring high-throughput batch processing with volume discounts
- —Users without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/111 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and network. However, there is no OpenAPI schema, no documentation beyond endpoint names, no request/response examples, and the specific purpose of /api/v1/charges/111 is undefined. The docs pages are empty. This is effectively a stub listing.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The specific endpoint /api/v1/charges/111 has no description beyond 'Premium API Access' — its actual functionality is unknown
- —No evidence of what data or service is actually returned upon successful payment
Citations
- —All endpoints priced at $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 Basehttps://lowpaymentfee.com/api/v1/charges/111
- —Platform offers endpoints for analytics, AI/ML, finance/Web3, and infrastructure utilitieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet' with no contenthttps://lowpaymentfee.com/docs