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/inbox/185` 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 listed endpoints share the same $0.02/request pricing. The platform claims no rate limits and no minimum commitments.
Important caveat: the `/api/v1/inbox/185` path does not clearly map to any of the named endpoints on the landing page. Its exact functionality is undocumented — the x402 challenge confirms it is live and accepts POST requests returning application/json, but there is no OpenAPI schema, request/response examples, or detailed documentation available. The /api, /pricing, and /README pages all resolve to a minimal "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Programmatic access to premium API content with per-call USDC micropayments
- —Agent-driven workflows that need keyless, on-demand API access on Base
- —Testing x402 payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that can sign USDC transactions on Base
- —Use cases requiring no-signup, pay-as-you-go API access
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Anyone without a Base-network USDC wallet
- —High-volume batch processing where per-call fees add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/185 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI schema, no request/response examples, and the inbox/185 path is unexplained. The /api, /pricing, and /README pages are empty. This is effectively a stub listing.
Warnings
- —The /api/v1/inbox/185 path does not correspond to any documented endpoint on the landing page — its actual functionality is unknown.
- —No OpenAPI schema, request examples, or response examples are available.
- —The /pricing, /api, and /README pages contain no useful content beyond a wallet-connect prompt.
- —The platform's claimed capabilities (AI, analytics, finance, etc.) cannot be verified for this specific endpoint.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/inbox/185
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/inbox/185
- —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