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, payable in USDC on the Base network with no API keys, rate limits, or commitments required.
The specific endpoint at `/api/v1/apikeys/20` is described 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 `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the "exact" scheme 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 price point. However, documentation is extremely thin: the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further technical detail, schemas, or usage examples. Without request/response schemas or sample payloads, it is unclear what inputs these endpoints expect or what outputs they return.
Capabilities
Use cases
- —Generating API keys for premium access via a single micropayment
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without subscriptions
- —Fetching real-time crypto quotes, gas estimates, and exchange rates on a per-call basis
- —Geocoding and data validation as utility microservices
- —Exporting data or retrieving analytics metrics with no upfront commitment
Fit
Best for
- —Developers who want pay-per-use API access without API key management
- —Agents and bots that can settle USDC payments on Base automatically
- —Projects needing low-cost, no-commitment access to diverse utility endpoints
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-throughput applications that need bulk pricing or SLAs
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/apikeys/20 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response documentation, and all doc pages render only 'Connect wallet'. The purpose of the specific /apikeys/20 endpoint is ambiguous. Effectively a stub listing.
Warnings
- —No OpenAPI or request/response schema available — input/output formats are unknown
- —All documentation pages (docs, API, pricing, README) return only 'Connect wallet' with no usable content
- —The exact purpose and response format of /api/v1/apikeys/20 is unclear from available material
- —No examples or sample payloads are documented anywhere
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/apikeys/20
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Docs, API, pricing, and README pages render only 'Connect wallet'https://lowpaymentfee.com/docs