Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that provides a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint `/api/v1/keys/26` 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 — no API keys, accounts, or subscriptions are required; callers simply attach an X-PAYMENT header with a valid payment proof.
The wider 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/request price point. The platform claims no rate limits and instant access.
However, the specific functionality behind `/api/v1/keys/26` ("Premium API Access") is not documented beyond its name. There is no OpenAPI schema, no request/response examples, and the crawled documentation pages (pricing, README, API) all returned only a "Connect wallet" prompt with no further content. The endpoint is confirmed live via a valid 402 challenge, but what it actually returns upon successful payment is unknown.
Capabilities
Use cases
- —Agents that need on-demand API access without managing API keys or subscriptions
- —Pay-per-use data analytics and reporting
- —Lightweight AI inference (sentiment, summarization, classification, embeddings) billed per call
- —Fetching real-time crypto gas estimates or token quotes with micropayments
- —Geocoding or data conversion without upfront commitments
Fit
Best for
- —AI agents needing frictionless, key-free API access via x402
- —Developers who want pay-as-you-go pricing with no minimums
- —Projects already operating on the Base network with USDC
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume workloads where $0.02/request adds up significantly compared to subscription-based alternatives
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/26 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is confirmed live via a valid x402 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no request/response examples, and no documentation explaining what '/api/v1/keys/26' actually does or accepts. The crawled docs pages were empty beyond wallet-connect prompts. This is effectively a stub listing.
Warnings
- —No documentation available — /api, /pricing, and /README pages all returned only 'Connect wallet' with no content
- —No OpenAPI or schema describing request parameters or response format for this endpoint
- —The purpose of '/api/v1/keys/26' ('Premium API Access') is completely undocumented — unclear what it returns
- —The broader platform lists many endpoint categories but none could be verified for actual functionality
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/26
- —All endpoints are priced at $0.02/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
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/keys/26