Pay-per-call API platform on Base via x402 — 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 suite of endpoints across four 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 endpoints are priced at $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no minimum commitments.
The specific endpoint at `/api/v1/charges/123` is listed as "Premium API Access" and returns a valid x402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme by including an X-PAYMENT header. The endpoint accepts POST requests and returns application/json responses. The payment recipient address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
Documentation beyond the landing page is sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no additional technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The actual functionality behind each endpoint is not described in detail, so the specific inputs and outputs remain unclear.
Capabilities
Use cases
- —Agent-driven data retrieval and analytics without managing API keys
- —On-demand AI inference (sentiment, summarization, classification, embeddings) paid per call
- —Fetching real-time crypto prices, gas estimates, and exchange rates via micropayments
- —Geocoding and data conversion utilities with no subscription commitment
- —Programmatic data export with pay-as-you-go pricing
Fit
Best for
- —AI agents needing keyless, pay-per-call access to diverse utility endpoints
- —Developers who want to avoid API key management and subscription overhead
- —Low-volume or bursty workloads where $0.02/request flat pricing is economical
Not for
- —High-volume production workloads where per-request costs would accumulate significantly
- —Users who need detailed API documentation, SLAs, or guaranteed uptime
- —Anyone without a Base-compatible USDC wallet for x402 payments
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/123 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI spec, no request/response schemas, no example payloads, and all documentation pages beyond the landing page are empty wallet-connect stubs. The actual functionality behind each endpoint is undocumented, making this effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — endpoint inputs and outputs are unknown
- —All doc pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content
- —The specific endpoint /api/v1/charges/123 is labeled 'Premium API Access' but is not listed among the advertised endpoints on the landing page — its purpose is unclear
- —No example requests or responses are documented anywhere
Citations
- —All endpoints priced at $0.02/request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/charges/123
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com