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 variety of endpoints across data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities. 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 commitments required. The x402 protocol handles payment inline: callers attach a payment header to each request and receive the response immediately.
The specific endpoint at `/api/v1/charges/287` is listed as "Premium API Access" and returns a 402 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 to the payTo 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 price point. However, 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 examples available. The actual behavior and data sources behind each endpoint are unknown.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification) without API key management
- —Fetching real-time crypto price feeds and gas estimates with per-call USDC payment
- —Geocoding or data conversion utilities paid per request via x402
Fit
Best for
- —Developers and agents wanting zero-signup, pay-as-you-go API access
- —x402-compatible wallets and agents on the Base network
- —Low-volume or sporadic API usage where subscriptions are wasteful
Not for
- —High-volume production workloads needing guaranteed SLAs and documented schemas
- —Users who need detailed API documentation, request/response examples, or OpenAPI specs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/287 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC payments on Base at $0.02/request. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page listing endpoint names, and no examples. The actual functionality behind '/api/v1/charges/287' (labeled only 'Premium API Access') is entirely opaque.
Warnings
- —No OpenAPI spec or schema documentation available for any endpoint
- —Docs, API, pricing, and README pages all render only 'Connect wallet' with no technical content
- —The specific endpoint /api/v1/charges/287 is labeled 'Premium API Access' but its actual functionality is undocumented — it does not appear in the landing page's endpoint list
- —Cannot verify what data or service is actually returned after payment
Citations
- —All endpoints priced at $0.02/request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/charges/287