Pay-per-call API platform on Base (USDC) covering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/payments/300` is labeled "Premium API Access" and charges up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys or rate limits are advertised; callers simply attach an x402 payment header to each request.
The site lists four endpoint categories: 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 utilities (geocoding, validation, conversion, generation). All listed endpoints share the same $0.02 per-request pricing.
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all resolve to a minimal "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material. The x402 challenge confirms the endpoint is live and accepts POST requests, but the actual behavior behind the paywall is unknown.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key signup
- —Fetching real-time financial data like token quotes, exchange rates, and gas estimates on a per-call basis
- —Running data analytics queries and exporting data with per-request billing
- —Using utility services like geocoding, validation, and format conversion via micropayments
Fit
Best for
- —Agents or developers who want instant, keyless API access with crypto micropayments
- —Low-volume or sporadic API consumers who prefer pay-per-use over subscriptions
- —x402-compatible AI agents that can autonomously pay for API calls on Base
Not for
- —Users who need detailed API documentation, schemas, or guaranteed SLAs before integrating
- —High-volume production workloads where per-request crypto settlement overhead matters
- —Developers who cannot or prefer not to pay in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/300 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and confirms pricing and network details, but documentation is effectively nonexistent — every doc page just shows 'Connect wallet'. No OpenAPI spec, no request/response schemas, and no examples are available. The actual functionality behind the paywall is unverifiable.
Warnings
- —Documentation pages (/docs, /pricing, /api, /README) contain no usable content — only a 'Connect wallet' prompt.
- —No OpenAPI or schema documentation is available; request and response formats are unknown.
- —The specific behavior of /api/v1/payments/300 ('Premium API Access') is unclear — it may be a generic or demo endpoint rather than a distinct service.
- —Cannot verify that the advertised AI, finance, data, and utility endpoints actually function as described.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/payments/300
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/payments/300