Pay-per-call API platform on Base (USDC) covering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint `/api/v1/keys/67` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). Payment is handled via the x402 protocol — callers attach an X-PAYMENT header with a signed payment to the payTo address, and the server fulfills the request upon verification.
The platform advertises four endpoint categories: 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 utilities (geocoding, validation, conversion, generation). All endpoints are listed at the same $0.02 price point. The site claims no API keys, no rate limits, no minimums, and instant access.
Important caveats: the specific endpoint probed (`/api/v1/keys/67`) does not clearly map to any of the documented API categories — it may be a key-management or access-provisioning endpoint. There is no OpenAPI schema, no request/response examples, and the docs pages (pricing, README, /api) all resolve to a minimal "Connect wallet" page with no additional detail. The actual behavior and response format of this endpoint are unknown.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto token quotes and gas estimates via micropayment
- —Geocoding or data validation as a utility service paid per call
- —Exporting analytics data or generating reports with no subscription commitment
Fit
Best for
- —AI agents that need low-friction, keyless API access paid in USDC on Base
- —Developers prototyping with multiple API categories without signing up for separate services
- —Micropayment-native workflows where $0.02/request is acceptable
Not for
- —High-volume production workloads where per-request costs add up quickly
- —Users who need detailed API documentation, SLAs, or guaranteed uptime
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/67 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response examples, and the documentation pages are empty stubs. The specific endpoint path (/api/v1/keys/67) doesn't match any documented API, making its purpose unclear. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — request/response formats are unknown
- —The endpoint path /api/v1/keys/67 does not correspond to any of the documented API categories on the landing page
- —Documentation pages (/pricing, /README, /api) all return only a 'Connect wallet' prompt with no content
- —No rate limit, SLA, or uptime information provided
- —Actual functionality behind this specific endpoint is unverified
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (asset 0x8335…) on Base networkhttps://lowpaymentfee.com/api/v1/keys/67
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com