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/90` 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 attach an X-PAYMENT header with a signed USDC payment to each request.
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, no minimums, and instant access.
This particular endpoint (`/api/v1/keys/90`) is labeled generically as "Premium API Access" and does not appear in the main catalog listing on the homepage. Its exact functionality is unclear — it may be a key-generation or key-management endpoint, or simply a generic premium tier access point. The endpoint is confirmed live, returning a valid x402 402 challenge on POST. No OpenAPI schema, request/response examples, or detailed documentation were found beyond the homepage catalog.
Capabilities
Use cases
- —Accessing data analytics and reports without signing up for an API key
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) on a per-call basis
- —Fetching real-time financial data such as exchange rates, token quotes, and gas estimates
- —Using utility endpoints like geocoding, validation, and conversion with instant crypto payment
Fit
Best for
- —Developers who want instant API access without account creation or subscriptions
- —Agents and bots that can settle payments in USDC on Base per request
- —Low-volume or sporadic API consumers who prefer pay-as-you-go pricing
Not for
- —High-volume consumers who need bulk pricing or subscription discounts
- —Users who cannot transact in USDC on the Base network
- —Anyone needing detailed API documentation or SLA guarantees before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/90 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is confirmed live via a valid x402 402 challenge, but there is no OpenAPI schema, no request/response examples, and no documentation explaining what /api/v1/keys/90 actually returns. The homepage lists other endpoints but not this one. Functionality must be guessed from the path name alone.
Warnings
- —The exact functionality of /api/v1/keys/90 is undocumented — it does not appear in the homepage catalog
- —No OpenAPI spec, request schema, or response schema is available
- —No detailed documentation pages were accessible (pricing, README, and /api pages all returned only a 'Connect wallet' prompt)
- —The platform's claims (no rate limits, instant access) are unverified
Citations
- —The endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/90
- —All listed endpoints cost $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
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/keys/90