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 pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys, rate limits, or subscriptions are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/charges/153` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this equals $0.02 per call, consistent with the site's advertised pricing. Payment is made via the x402 "exact" scheme to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — all at the same $0.02 price point. However, no OpenAPI schema, detailed documentation, or example request/response payloads were found in the crawl. The docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content. The exact capabilities and response formats of this specific endpoint (charges/153) are unclear from available material.
Capabilities
Use cases
- —Agents making ad-hoc API calls without needing pre-registered API keys
- —On-demand AI inference (sentiment, summarization, classification) with per-call crypto payment
- —Fetching real-time crypto quotes, gas estimates, or exchange rates via micropayment
- —Geocoding or data validation without subscription commitments
Fit
Best for
- —AI agents and bots that need keyless, pay-per-use API access
- —Developers experimenting with x402 protocol integrations
- —Low-volume or sporadic API consumers who want to avoid subscriptions
Not for
- —High-volume production workloads needing guaranteed SLAs and detailed documentation
- —Users without a Base-network USDC wallet or x402-compatible client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/153 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no OpenAPI schema, no documentation beyond a landing page listing, no example requests or responses, and the specific purpose of '/api/v1/charges/153' ('Premium API Access') is entirely opaque. The docs/pricing/README pages are empty stubs.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The specific function of /api/v1/charges/153 ('Premium API Access') is not described anywhere — it is unclear what data or service it returns
- —All documentation pages (docs, api, pricing, README) returned only 'Connect wallet' with no content
- —No example request or response payloads are available to confirm endpoint behavior
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/charges/153
- —Payment address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with 300-second timeouthttps://lowpaymentfee.com/api/v1/charges/153