Pay-per-call API platform on Base network via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, paid in USDC on the Base network using the x402 payment protocol. No API keys, rate limits, or upfront commitments are required — callers simply attach an X-PAYMENT header with a valid x402 payment to access any endpoint.
The specific endpoint at `/api/v1/charges/280` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USDC, i.e., $0.02) on Base. The platform advertises categories including 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 (geocoding, validation, conversion, generation).
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no detailed documentation for any endpoint. The endpoint is confirmed live via a valid 402 challenge, but without documentation it is unclear what inputs this specific endpoint expects or what it returns.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates on a per-call basis
- —Running data analytics queries and exporting data with per-request billing
- —Using utility services like geocoding, validation, and conversion without subscriptions
Fit
Best for
- —Agents and bots that need frictionless, keyless API access via crypto micropayments
- —Developers prototyping with multiple API categories without committing to subscriptions
- —x402-compatible clients on the Base network looking for low-cost per-call endpoints
Not for
- —Users who need detailed API documentation, schemas, or guaranteed SLAs before integrating
- —High-volume production workloads where $0.02/request adds up and bulk pricing would be preferred
- —Users without USDC on Base or without x402-compatible payment infrastructure
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/280 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and the landing page provides a catalog overview with pricing. However, there is no OpenAPI schema, no request/response examples, and all documentation pages render only 'Connect wallet' with no content. The specific purpose of /api/v1/charges/280 ('Premium API Access') is unclear beyond its name.
Warnings
- —No API documentation available — docs, API, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or JSON schema provided for any endpoint
- —The specific functionality of /api/v1/charges/280 ('Premium API Access') is not documented — it is unclear what it does or what inputs it expects
- —Cannot verify that the advertised AI, finance, and utility endpoints actually function as described
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —402 challenge requests maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/charges/280