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/31` 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.
However, the specific endpoint being listed here (`/api/v1/keys/31`) does not clearly map to any of the named endpoints on the site. Its description is simply "Premium API Access," and no documentation, request/response schema, or usage examples are available. The crawled docs pages (/api, /pricing, /README) all returned only a "Connect wallet" prompt with no substantive content. Without further documentation it is unclear what this particular endpoint returns or what input it expects beyond a POST request.
Capabilities
Use cases
- —Programmatic access to paid API endpoints without needing an account or API key
- —Agent-driven workflows that need to pay for API calls on-the-fly using USDC on Base
- —Accessing premium data or utility services with per-request micropayments
Fit
Best for
- —Developers or agents who want zero-signup, pay-as-you-go API access
- —Use cases requiring micropayment-settled API calls on Base L2
- —Scenarios where avoiding API key management is desirable
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume use cases where per-request pricing at $0.02 may not be cost-effective compared to subscription APIs
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/31 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge) and pricing is clear ($0.02 USDC on Base). However, there is no documentation for this specific endpoint, no request/response schema, no examples, and the purpose of /api/v1/keys/31 is ambiguous. The crawled doc pages were empty. This is effectively a stub listing.
Warnings
- —No documentation available for /api/v1/keys/31 — purpose and expected input/output are unknown
- —All documentation pages (/api, /pricing, /README) returned only a 'Connect wallet' prompt with no content
- —The endpoint path '/api/v1/keys/31' does not match any of the named endpoints listed on the homepage
- —No OpenAPI spec, no AI plugin manifest, no robots.txt, no agents.txt found
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/31
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/keys/31