Pay-per-request API platform on Base network via x402 — $0.02/call in USDC.
What it does
lowpaymentfee.com is an x402-enabled API marketplace offering a broad set of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. 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/products/77` is labeled "Premium API Access" and returns `application/json` via POST.
The platform advertises four main categories of APIs: 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 flow — callers send a POST with an `X-PAYMENT` header containing a signed payment proof, and the server returns the requested data.
The `/api/v1/products/77` endpoint was probed and returned a valid 402 challenge with `maxAmountRequired` of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base, 6 decimals), which equals $0.02. Payment is sent to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` with a 300-second timeout. No OpenAPI schema, detailed documentation, or example responses were found — the docs, pricing, and API pages all render only a "Connect wallet" prompt with no further content.
Capabilities
Use cases
- —Accessing premium API data without signing up for an account or managing API keys
- —Making one-off paid API calls from an AI agent using x402 USDC payments on Base
- —Integrating pay-as-you-go analytics, AI inference, or finance data into automated workflows
Fit
Best for
- —Developers wanting zero-friction, keyless API access via crypto micropayments
- —AI agents that can autonomously pay for API calls using x402 protocol
- —Projects already operating on the Base L2 network with USDC
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —Teams requiring fiat payment options or invoicing
- —High-volume consumers who need bulk pricing or rate-limit guarantees
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/77 \
-H "X-PAYMENT: <x402-signed-payment-proof>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no OpenAPI schema, no documentation beyond a landing page listing, no example request/response bodies, and no description of what /api/v1/products/77 actually returns. The docs/pricing/API pages are all blank ("Connect wallet" only). This is effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The docs, pricing, and API pages render only 'Connect wallet' with no usable content
- —The specific purpose of /api/v1/products/77 ('Premium API Access') is undefined — no description of what data it returns
- —No example responses available to verify endpoint functionality beyond the 402 challenge
Citations
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The 402 challenge for /api/v1/products/77 specifies maxAmountRequired of 20000 base units of USDC on Base with a 300-second timeouthttps://lowpaymentfee.com/api/v1/products/77
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/products/77
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com