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 infrastructure utilities. All endpoints are paid per-request using USDC on the Base network, with no API keys, no rate limits, and no minimum commitments required. The specific endpoint at `/api/v1/charges/177` is labeled "Premium API Access" and accepts x402 payments.
The platform advertises a flat $0.02 per request across its listed endpoints. The probed endpoint's x402 challenge shows a maxAmountRequired of 20000 base units of USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base), which equals $0.02 given USDC's 6 decimals. The payment scheme is "exact" with a 300-second timeout. The site lists endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, conversion, and more — all at the same price point.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional content. There is no OpenAPI schema, no request/response examples, and no detailed documentation for any endpoint. The actual functionality behind `/api/v1/charges/177` ("Premium API Access") is not described beyond its title, so it is unclear what data or service it returns.
Capabilities
Use cases
- —Agents that need on-demand API access without pre-registration or API keys
- —Paying per-call for AI inference tasks like sentiment analysis or text summarization
- —Fetching financial data such as token quotes, exchange rates, or gas estimates
- —Utility operations like geocoding, validation, or data conversion
Fit
Best for
- —AI agents needing keyless, pay-as-you-go API access
- —Developers wanting low-friction API consumption via crypto micropayments
- —Use cases requiring no rate limits and instant access
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Applications requiring non-crypto payment methods
- —High-volume use cases where $0.02/request adds up significantly
Quick start
# POST with x402 payment header to access the endpoint
curl -X POST https://lowpaymentfee.com/api/v1/charges/177 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no documentation, no OpenAPI schema, no request/response examples, and the specific functionality of this 'Premium API Access' endpoint is entirely undescribed. The docs/pricing/API pages are all empty beyond a wallet connect prompt.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The specific purpose of /api/v1/charges/177 ('Premium API Access') is not documented anywhere
- —No request or response examples available to verify actual functionality
Citations
- —Flat pricing of $0.02 per request across all endpointshttps://lowpaymentfee.com
- —No API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units USDC on Base with 300s timeouthttps://lowpaymentfee.com/api/v1/charges/177
- —USDC asset contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/charges/177
- —Endpoint categories include Data & Analytics, AI & ML, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com