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, and infrastructure utilities. All endpoints are paid per-request using USDC on the Base network, with no API keys, no rate limits, and no commitments required. The specific endpoint at `/api/v1/transfers/199` is labeled "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 per call (USDC uses 6 decimals).
The platform advertises a broad catalog of endpoints including sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, conversion, and data export — all at the same $0.02 price point. Payment is handled via the x402 protocol's "exact" scheme, settling on-chain to a specified payTo address. The x402 challenge specifies a 300-second timeout and accepts POST requests.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what the endpoints actually return. The endpoint probed (`/api/v1/transfers/199`) has a generic "Premium API Access" description that does not clarify what data or functionality it provides.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates on a per-call basis
- —Running utility operations like geocoding, validation, and data conversion with micropayments
Fit
Best for
- —Developers who want keyless, pay-per-use API access settled in USDC on Base
- —Agents and bots that need programmatic access to diverse API endpoints via x402
- —Projects needing low-cost micropayment-gated API calls without subscriptions
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk pricing or rate-limited plans
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transfers/199 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it is operational. However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response examples, and the specific endpoint's purpose ('Premium API Access' at /api/v1/transfers/199) is unclear. The broad catalog is listed on the homepage but without any detail on inputs or outputs.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all render only 'Connect wallet' with no usable content
- —No OpenAPI or schema documentation available for any endpoint
- —The specific endpoint /api/v1/transfers/199 has a vague 'Premium API Access' label — its actual functionality is unknown
- —No request body schema or response schema documented anywhere
- —Cannot verify that the advertised AI/ML, finance, and utility endpoints actually function as described
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with 300s timeouthttps://lowpaymentfee.com/api/v1/transfers/199
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com