Pay-per-call API platform on Base (USDC) covering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/keys/75` 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 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 listed endpoints share the same $0.02/request pricing with no rate limits or minimum commitments.
Important caveat: the specific endpoint `/api/v1/keys/75` has a generic "Premium API Access" description and no documentation explaining what it actually returns. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawled pages. The platform's docs, pricing, and README pages all resolve to a minimal "Connect wallet" prompt with no further content. Prospective callers should treat this as a low-documentation endpoint and test with a small payment first.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data such as token quotes, gas estimates, and exchange rates via micropayments
- —Accessing utility services like geocoding, validation, and data conversion on a per-request basis
Fit
Best for
- —AI agents that need keyless, pay-as-you-go API access
- —Developers wanting low-friction access to multiple endpoint categories without subscriptions
- —x402-compatible wallets and agent frameworks on the Base network
Not for
- —High-volume batch processing where per-request pricing becomes expensive
- —Users who need detailed API documentation and guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/75 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (returns a valid x402 402 challenge), but there is zero documentation on what `/api/v1/keys/75` actually does or returns. No OpenAPI spec, no request/response schemas, and no examples are available. The docs/pricing/README pages are empty beyond a wallet-connect prompt. The listing is effectively a stub.
Warnings
- —No documentation available for the specific endpoint /api/v1/keys/75 — its purpose and response format are unknown
- —No OpenAPI or schema definitions found anywhere on the site
- —Docs, pricing, and README pages all resolve to a minimal 'Connect wallet' page with no content
- —The endpoint name 'Premium API Access' is generic and does not describe functionality
Citations
- —The endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/75
- —All listed endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/keys/75