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 broad collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. Every endpoint costs $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no upfront commitments. The specific endpoint at `/api/v1/transactions/126` is listed as "Premium API Access" and returns an x402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base.
The platform advertises categories including 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 (geocoding, validation, conversion, generation). All endpoints appear to follow the same x402 payment pattern: send a POST with an X-PAYMENT header containing a valid payment proof, and receive a JSON response.
Documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "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 crawl. The endpoint is confirmed live (402 challenge captured), but without documentation it is unclear what request body the `/api/v1/transactions/126` endpoint expects or what it returns.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data and crypto quotes with per-request USDC micropayments
- —Using utility services like geocoding and data validation on a pay-as-you-go basis
- —Programmatic data export and analytics without subscription commitments
Fit
Best for
- —Agents or developers who want keyless, pay-per-call API access settled in USDC on Base
- —Low-volume or bursty workloads where subscription pricing is wasteful
- —Web3-native applications that already hold USDC on Base
Not for
- —High-volume production workloads needing SLAs, rate-limit guarantees, or detailed documentation
- —Users without a Base-compatible wallet or USDC holdings
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/126 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, and pricing is clear ($0.02 USDC per request). However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page listing, and no examples. The specific endpoint path (/api/v1/transactions/126) has no description beyond 'Premium API Access', making it essentially a stub.
Warnings
- —No OpenAPI or schema documentation available — request/response formats are unknown
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content
- —The specific endpoint /api/v1/transactions/126 is not listed among the advertised APIs on the landing page — its purpose is unclear
- —No rate limit or SLA information provided
Citations
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge for this endpoint requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/126
- —Platform offers endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com