Pay-per-request API platform on Base (USDC) via x402 — $0.02/call, no keys required.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint `/api/v1/inbox/158` is listed as "Premium API Access" and costs up to $0.02 per request (maxAmountRequired of 20,000 base units of USDC with 6 decimals). No API keys, accounts, or rate limits are advertised — callers simply attach an x402 payment header to each POST request.
The broader platform advertises multiple API categories including 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 per request price point.
However, the specific functionality behind `/api/v1/inbox/158` is not documented beyond the generic label "Premium API Access." There is no OpenAPI schema, no request/response examples, and no detailed documentation available from the crawled pages. The endpoint is confirmed live (returns a valid 402 x402 challenge), but what data or service it actually provides when paid is unknown from the available material.
Capabilities
Use cases
- —Accessing a pay-per-request API endpoint without needing API keys or subscriptions
- —Making programmatic USDC micropayments on Base for API access
- —Integrating x402-compatible agent workflows with low-cost API calls
Fit
Best for
- —Developers wanting zero-signup API access via crypto micropayments
- —AI agents with x402 payment capability looking for low-cost endpoints
- —Users who prefer pay-as-you-go pricing without rate limits
Not for
- —Users who need detailed API documentation or guaranteed SLAs before purchasing
- —Anyone without a Base-network USDC wallet or x402-compatible client
- —High-volume users who would benefit from bulk pricing or subscriptions
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/158 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, but there is no documentation, no OpenAPI schema, no request/response examples, and the actual functionality behind 'Premium API Access' at /api/v1/inbox/158 is completely undocumented. This is effectively a stub listing.
Warnings
- —No documentation exists for what /api/v1/inbox/158 actually does when paid — 'Premium API Access' is a generic label
- —No OpenAPI schema, request format, or response examples are available
- —The /api, /pricing, and /README pages all returned only 'Connect wallet' with no useful content
- —Cannot verify what service or data is delivered after payment
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/158
- —The platform lists $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/inbox/158
- —Multiple API categories are advertised including Data & Analytics, AI & ML, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com