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/176` is listed as "Premium API Access" and accepts POST requests with an x402 payment challenge requiring up to 20,000 base units of USDC (i.e., $0.02 per call, since USDC uses 6 decimals). No API keys or rate limits are advertised; callers simply attach an X-PAYMENT header to each request.
The wider platform advertises four endpoint families: 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 endpoint probed here (`/api/v1/inbox/176`) does not clearly map to any of those named categories, and no documentation, OpenAPI spec, or response schema was found for it.
Payments are settled on Base to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`). The x402 challenge specifies version 1, scheme "exact", and a 300-second payment timeout. The endpoint is live and returns a proper 402 challenge.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint with per-call USDC micropayments
- —Agent-driven workflows that need keyless, on-demand API access settled on Base
- —Integrating pay-as-you-go API calls without subscription commitments
Fit
Best for
- —Developers or agents who want zero-signup, pay-per-use API access
- —Users already holding USDC on Base who want frictionless micropayments
- —Prototyping or low-volume use cases where $0.02/call is cost-effective
Not for
- —Users who need detailed documentation or guaranteed SLAs before integrating
- —High-volume production workloads where per-call crypto settlement adds overhead
- —Anyone without a Base-compatible wallet or USDC holdings
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/176 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Example
Request
{
"url": "https://lowpaymentfee.com/api/v1/inbox/176",
"body": {},
"method": "POST",
"headers": {
"X-PAYMENT": "<x402-payment-token>",
"Content-Type": "application/json"
}
}Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is no OpenAPI spec, no documentation, no response schema, and no explanation of what /api/v1/inbox/176 actually does. The 'Premium API Access' label is generic and uninformative. The broader site lists many endpoints but provides no docs for any of them. This is effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for this endpoint or any endpoint on the platform
- —The specific path /api/v1/inbox/176 does not correspond to any named endpoint in the site's catalog — its actual functionality is unknown
- —No example responses or error codes documented anywhere
- —The /api, /pricing, and /README pages all returned only 'Connect wallet' with no useful content
- —Cannot verify what data or service this endpoint actually provides
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/176
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/inbox/176
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform advertises four endpoint families: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com