Pay-per-call premium API access on Base via x402 — $0.02 per 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/11` is listed as "Premium API Access" and returns a valid x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0x8335… on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme to the specified payTo address. 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/11` actually returns. The site's landing page lists many API paths but none match the `/api/resource/11` pattern, making it unclear what this specific resource provides. Prospective callers should be aware that the actual functionality behind this endpoint is undocumented.
Capabilities
Use cases
- —Accessing a paid API resource without traditional API key registration
- —Making micropayment-gated API calls settled in USDC on Base
- —Agent-driven programmatic access to premium content or data
Fit
Best for
- —Developers wanting keyless, pay-per-call API access
- —AI agents with x402-compatible payment capabilities
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing well-documented API contracts with clear request/response schemas
- —Anyone without a Base-compatible USDC wallet
- —High-volume consumers who would benefit from bulk pricing or subscriptions
Quick start
# 1. Send a POST to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/resource/11
# 2. Parse the 402 response, construct an X-PAYMENT header
# with a signed USDC payment of 20000 base units ($0.02)
# on Base to 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3
# 3. Resend the POST with the X-PAYMENT header attached.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is zero documentation on what /api/resource/11 actually does or returns. No OpenAPI spec, no request/response examples, and the docs pages are empty. The specific resource path doesn't match any of the advertised API routes on the landing page.
Warnings
- —No documentation available — /docs, /pricing, /README all render only 'Connect wallet' with no content.
- —The endpoint path /api/resource/11 does not match any of the advertised API routes listed on the homepage.
- —No request or response schema is documented; callers cannot know what data to send or expect back.
- —Functionality behind this specific endpoint is entirely unknown.
Citations
- —All endpoints priced at $0.02 per 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 (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/resource/11
- —Site lists APIs for data & analytics, AI & ML, finance & Web3, and infrastructure utilitieshttps://lowpaymentfee.com