Pay-per-call API key generation on Base via x402 — $0.02 per request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, paid in USDC on the Base network with no API keys, rate limits, or commitments required.
The specific endpoint at `/api/v1/apikeys/45` is listed as "Premium API Access." Based on the x402 challenge, it accepts POST requests and charges up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is settled on-chain 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 generation — all at the same $0.02/request price point. Documentation pages (docs, pricing, README) returned only a "Connect wallet" prompt with no further technical detail, so the actual request/response schemas for this and other endpoints remain undocumented in the crawl material.
Capabilities
Use cases
- —Agents purchasing one-off API access without managing API keys or subscriptions
- —Programmatic access to AI inference endpoints (sentiment, summarization, classification, embeddings) with per-call crypto payment
- —Fetching real-time financial data such as token quotes, gas estimates, and exchange rates via micropayments
- —Using utility services like geocoding, validation, and data conversion on a pay-as-you-go basis
Fit
Best for
- —AI agents that need frictionless, keyless API access paid per call
- —Developers wanting to avoid subscription commitments for low-volume API usage
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads where per-call pricing at $0.02 would be cost-prohibitive compared to bulk plans
- —Users who cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/apikeys/45 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and confirms pricing and payment details, but documentation pages are empty (only 'Connect wallet'), no OpenAPI spec is available, and request/response schemas are entirely absent. The purpose of the specific /apikeys/45 endpoint is unclear beyond its title.
Warnings
- —Documentation pages (/docs, /pricing, /README) returned no usable content — only a 'Connect wallet' prompt.
- —No OpenAPI spec or request/response schema available for any endpoint.
- —The exact purpose and expected input/output of /api/v1/apikeys/45 ('Premium API Access') is not documented; it may differ from the other listed endpoints.
- —The broader platform lists many endpoints (AI, finance, utils) but none have documented schemas or example payloads in the crawl material.
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or commitmentshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913)https://lowpaymentfee.com/api/v1/apikeys/45
- —Payment address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with 300-second timeouthttps://lowpaymentfee.com/api/v1/apikeys/45
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com