Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The site advertises a broad suite of APIs spanning data & analytics, 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, payable in USDC on the Base network with no API keys, no rate limits, and no commitments required.
The specific endpoint `/api/resource/13` is listed as "Premium API Access" and returns a valid x402 402 challenge. The challenge specifies payment of up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 using the "exact" scheme. The endpoint accepts POST requests and returns application/json.
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 `/api/resource/13` actually returns. The site's landing page lists many API paths but does not clarify what this particular resource ID maps to. Treat this as a low-documentation endpoint where the actual payload and behavior must be discovered experimentally.
Capabilities
Use cases
- —Accessing premium data or AI endpoints without API key registration
- —Making one-off paid API calls settled in USDC on Base
- —Agent-driven workflows that need instant, keyless API access with crypto micropayments
Fit
Best for
- —Developers wanting zero-signup, pay-per-use API access
- —AI agents with Base USDC wallets needing on-demand endpoints
- —Prototyping integrations without committing to subscription plans
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume use cases where $0.02/request adds up and bulk pricing is preferred
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/resource/13 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no documentation beyond a landing page listing, no request/response schema, and no examples. The specific resource '/api/resource/13' is not explained anywhere. This is effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — endpoint behavior must be discovered experimentally
- —The /docs, /pricing, /api, and /README pages all render only 'Connect wallet' with no usable content
- —The meaning of '/api/resource/13' is not documented; it is unclear what this specific resource returns
- —No request body schema or response examples are available
Citations
- —All endpoints priced at $0.02/request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge specifies maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/resource/13
- —Site lists APIs for data & analytics, AI & ML, finance & Web3, and infrastructure utilitieshttps://lowpaymentfee.com