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/25` is listed as "Premium API Access" and costs up to $0.02 per call (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 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 listed endpoints share the same $0.02/request pricing. The x402 challenge confirms the endpoint is live, accepts POST requests, and settles via the USDC contract on Base (0x8335…2913).
Note that the specific functionality behind `/api/v1/keys/25` ("Premium API Access") is not clearly documented — it may serve as a key-provisioning or meta-access endpoint rather than one of the domain-specific APIs listed on the homepage. No OpenAPI schema, request/response examples, or detailed documentation were found during crawling; the /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification) without subscription overhead
- —Fetching real-time financial data or crypto gas estimates with per-call billing
- —Geocoding or data validation as a utility service paid in USDC
- —Exporting analytics data or generating insights on a pay-as-you-go basis
Fit
Best for
- —AI agents that need low-friction, keyless API access settled on-chain
- —Developers wanting per-request pricing with no minimums or commitments
- —Web3-native applications that already hold USDC on Base
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk/subscription pricing
- —Teams requiring SLA guarantees or enterprise support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/25 \
-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), but there is no OpenAPI schema, no request/response examples, and no documentation beyond a homepage listing. The specific purpose of /api/v1/keys/25 is ambiguous. Most crawled pages returned only 'Connect wallet' with no useful content.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The specific function of /api/v1/keys/25 ('Premium API Access') is unclear — it may be a meta/key-provisioning endpoint rather than a domain API
- —All non-homepage pages (/api, /pricing, /README) returned only 'Connect wallet' with no documentation
- —No request or response examples are available; integration requires trial-and-error
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/25
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/keys/25
- —Platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories all at $0.02/requesthttps://lowpaymentfee.com
- —No API keys, no rate limits, no commitments advertisedhttps://lowpaymentfee.com