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 at `/api/v1/keys/3` is labeled "Premium API Access" and charges up to $0.02 per request (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an x402 payment header to each request.
The platform advertises four categories of endpoints: 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 listed endpoints share the same $0.02 per-request pricing. The x402 challenge confirms the endpoint is live, uses the "exact" payment scheme on Base, and accepts USDC (contract 0x8335…2913).
Note that while the landing page lists many endpoints, only `/api/v1/keys/3` was probed and confirmed live. There is no OpenAPI spec, no detailed request/response documentation, and the crawled sub-pages (/api, /pricing, /README) returned only a "Connect wallet" prompt with no additional content. The actual behavior and response format of this specific endpoint — and whether it serves as a key-generation or key-retrieval service — is unclear from available materials.
Capabilities
Use cases
- —Agents that need on-demand AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates with per-call billing
- —Running geocoding, validation, or data conversion tasks with zero upfront commitment
- —Exporting analytics data or generating reports on a pay-as-you-go basis
Fit
Best for
- —AI agents needing keyless, pay-per-call access to diverse utility endpoints
- —Developers who want to avoid subscription commitments for low-volume API usage
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads where per-call pricing at $0.02 would be expensive at scale
- —Users who need detailed API documentation, SLAs, or guaranteed uptime
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/3 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page listing, and the specific purpose of /api/v1/keys/3 is ambiguous. Sub-pages returned no useful content.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The purpose and expected input/output of /api/v1/keys/3 ('Premium API Access') is not documented
- —Sub-pages (/api, /pricing, /README) returned only 'Connect wallet' with no content
- —Many endpoints are advertised on the landing page but only /api/v1/keys/3 was confirmed live
- —No information about uptime, SLAs, or the team behind the service
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/3
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/keys/3
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Four endpoint categories listed: Data & Analytics, AI & Machine Learning, Finance & Web3, Infrastructurehttps://lowpaymentfee.com