x402-gated premium API access on Base, pay $0.02 per request in USDC — no keys, no rate limits.
What it does
lowpaymentfee.com is an x402-enabled API platform offering a suite of endpoints across data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. All endpoints are pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys or accounts are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/charges/17` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment scheme is "exact" with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.
The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02/request price point. Documentation pages exist but appear to require a wallet connection and contain no visible content in the crawl. As a result, request/response schemas for individual endpoints are not documented in the available material.
Capabilities
Use cases
- —Agents that need on-demand API access without pre-registration or API keys
- —Paying per-call for miscellaneous utility endpoints (geocoding, validation, conversion)
- —Accessing AI inference (sentiment, summarization, classification, embeddings) with crypto micropayments
- —Fetching financial data (prices, exchange rates, gas estimates) via x402 payment
Fit
Best for
- —AI agents with x402 payment capability on Base
- —Developers who want zero-signup, pay-as-you-go API access
- —Applications needing low-cost ($0.02) per-request utility or AI endpoints
Not for
- —Users without USDC on Base network
- —High-volume batch workloads where per-request pricing may add up
- —Anyone needing detailed API documentation before integrating (docs are sparse)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/17 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, and the landing page lists available APIs with pricing. However, there is no OpenAPI spec, no request/response schema documentation, and the docs/pricing/README pages are all blank (wallet-gated). The specific purpose of '/api/v1/charges/17' beyond 'Premium API Access' is unclear — it may be a generic charge endpoint rather than a specific functional API.
Warnings
- —Documentation pages (/docs, /pricing, /README, /api) are wallet-gated and contain no visible content
- —No OpenAPI or machine-readable schema available
- —The endpoint path '/api/v1/charges/17' does not clearly map to any of the advertised functional APIs listed on the homepage
- —Request and response body formats are completely undocumented
- —The exact functionality behind 'Premium API Access' is ambiguous — it may be a generic payment endpoint
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with 300s timeouthttps://lowpaymentfee.com/api/v1/charges/17
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com