Pay-per-request premium API access on Base via x402 — $0.02/call in USDC.
What it does
This endpoint at lowpaymentfee.com provides a pay-per-request API service settled via the x402 protocol on the Base network using USDC. The specific endpoint `/api/v1/inbox/170` is labeled "Premium API Access" and charges up to 20,000 base units of USDC (i.e., $0.02 per request, since USDC uses 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an x402 payment header to each POST request.
The broader lowpaymentfee.com platform advertises a suite of endpoints across four 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 $0.02 per request. However, the specific `/api/v1/inbox/170` endpoint does not clearly map to any of these named services — its purpose beyond "Premium API Access" is not documented.
The endpoint is live and returns a valid x402 challenge (HTTP 402) with scheme "exact" on the Base network, paying to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`. The maximum timeout is 300 seconds. No OpenAPI schema, detailed documentation, or example responses are available for this specific endpoint.
Capabilities
Use cases
- —Accessing premium API functionality with per-request USDC micropayments on Base
- —Agent-driven workflows that need keyless, on-demand API access
- —Programmatic access to data, AI, finance, or utility endpoints without subscriptions
Fit
Best for
- —Developers or agents who want zero-commitment, pay-as-you-go API access
- —x402-compatible clients on the Base network
- —Use cases requiring low-cost ($0.02) per-request billing without API key management
Not for
- —Users who need detailed API documentation or guaranteed SLAs before purchasing
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Callers not equipped with x402 payment capabilities or USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/170 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Example
Request
{
"url": "https://lowpaymentfee.com/api/v1/inbox/170",
"body": {},
"method": "POST",
"headers": {
"X-PAYMENT": "<x402-payment-token>",
"Content-Type": "application/json"
}
}Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but the specific functionality of /api/v1/inbox/170 is undocumented. No OpenAPI schema, no example responses, and no detailed docs are available. The broader site lists many endpoints but provides no specifics on request/response formats. This is effectively a stub listing.
Warnings
- —The specific purpose of /api/v1/inbox/170 ('Premium API Access') is not documented — it does not match any of the named endpoints on the site.
- —No OpenAPI schema, request/response examples, or detailed documentation available for this endpoint.
- —The /api, /pricing, and /README pages all returned only a 'Connect wallet' prompt with no useful content.
- —Cannot verify what data or service this endpoint actually returns without making a paid request.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/170
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/inbox/170