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 exposes a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/inbox/66` is listed as "Premium API Access" and accepts POST requests with a maximum cost of $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys or rate limits are advertised; callers pay per request via the x402 protocol's X-PAYMENT header.
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. However, the specific functionality behind `/api/v1/inbox/66` is not documented beyond the generic "Premium API Access" label, so its exact behavior is unclear.
The endpoint is live and returns a well-formed x402 challenge (version 1, scheme "exact") with payment directed to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) on Base. The timeout is 300 seconds. No OpenAPI schema, detailed request/response documentation, or usage examples were found in the crawl.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint without managing API keys or subscriptions
- —Agent-driven workflows that need on-demand, pay-per-call data or utility services
- —Testing x402 protocol integrations with a low-cost live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol on Base
- —AI agents that need keyless, pay-as-you-go API access
- —Low-volume or bursty workloads where per-request pricing is preferable to subscriptions
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume production workloads where $0.02/request adds up significantly
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/66 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but the specific functionality of /api/v1/inbox/66 is completely undocumented. No OpenAPI schema, no request/response examples, and no description beyond the generic 'Premium API Access' label. The crawl yielded only a landing page listing other endpoints and wallet-connect stubs for docs/pricing pages.
Warnings
- —The exact functionality of /api/v1/inbox/66 is unknown — 'Premium API Access' is the only description available
- —No OpenAPI or request/response schema was found; callers cannot know what to send or expect back
- —Documentation, pricing, and README pages all returned only a 'Connect wallet' stub with no useful content
- —The platform lists many endpoint categories but none map clearly to /api/v1/inbox/66
Citations
- —Endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/66
- —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
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 and payTo is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3https://lowpaymentfee.com/api/v1/inbox/66