Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
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/transactions/166` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) per call. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform offers 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 priced at $0.02 per request.
This particular endpoint (`/api/v1/transactions/166`) is labeled "Premium API Access" but the crawled material does not clarify what data or functionality it returns beyond the generic label. The docs, pricing, and README pages all rendered only a "Connect wallet" prompt with no additional documentation. Without further documentation or example responses, the exact behavior of this endpoint remains unclear.
Capabilities
Use cases
- —Programmatic access to premium API data with per-request USDC micropayments
- —Agent-driven workflows that need keyless, on-demand API calls settled on Base
- —Testing x402 payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 protocol payments
- —AI agents that need frictionless pay-per-call access without API key provisioning
- —Low-volume consumers who prefer per-request pricing over subscriptions
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume consumers who would benefit from bulk pricing or subscription plans
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/166 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no documentation beyond a landing page, no example request/response, and the specific functionality of this endpoint is undocumented. The docs/pricing/README pages all return only 'Connect wallet' with no content.
Warnings
- —The exact functionality of /api/v1/transactions/166 ('Premium API Access') is not documented anywhere in the crawled material.
- —All documentation pages (docs, pricing, README, api) returned only 'Connect wallet' with no substantive content.
- —No OpenAPI spec, no example requests or responses, and no input schema are available.
- —The platform lists many endpoint categories (AI, analytics, finance, infrastructure) but none are documented beyond a name and price.
Citations
- —Endpoint returns 402 with x402 challenge requesting up to 20,000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/transactions/166
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/166
- —Platform offers endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com