Pay-per-call API platform on Base (USDC) via x402 — data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of 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, payable in USDC on the Base network with no API keys, no rate limits, and no minimum commitments.
The specific endpoint `/api/v1/customers/21` is listed as "Premium API Access" and returns a valid x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme by including an X-PAYMENT header. The endpoint accepts POST requests and returns application/json.
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 spec, no request/response schema documentation, and no usage examples available. The exact purpose of the `/api/v1/customers/21` resource is unclear from the available material; it does not appear in the main catalog listing, which focuses on analytics, AI, finance, and utility endpoints.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, exchange rates, and gas estimates
- —Running data analytics queries and exporting reports on a per-request payment basis
- —Geocoding and data validation as utility microservices
Fit
Best for
- —Agents or developers who want zero-signup, pay-per-call API access
- —Use cases requiring low-cost micropayments ($0.02/call) settled on Base L2
- —Projects already holding USDC on Base that need quick API integrations
Not for
- —Users without a Base-compatible wallet or USDC holdings
- —Applications requiring detailed API documentation, SDKs, or guaranteed SLAs
- —High-volume use cases where subscription pricing would be more economical
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/customers/21 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, and the landing page provides a catalog overview with pricing. However, there is no OpenAPI spec, no request/response schemas, no documentation beyond a wallet-connect prompt, and the specific /api/v1/customers/21 endpoint is not described in the catalog. The listing is effectively a stub with pricing info.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The /api/v1/customers/21 path does not appear in the site's published API catalog — its purpose is unclear
- —All documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet' with no content
- —No request or response examples are available anywhere in the crawled material
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 (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/customers/21
- —Catalog includes Data & Analytics, AI & ML, Finance & Web3, and Infrastructure endpoint categorieshttps://lowpaymentfee.com
- —Documentation pages render only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs