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/trades/135` 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/trades/135`) falls under a "trades" path that is not explicitly listed on the site's landing page among the documented API categories. Its exact functionality is unclear — the description simply says "Premium API Access" and no further documentation, request schema, or response schema is available. The docs, pricing, and API pages all render only a "Connect wallet" prompt with no additional content. Callers should be aware that the actual behavior of this endpoint is undocumented beyond its x402 challenge metadata.
Capabilities
Use cases
- —Accessing trade data or premium content behind a per-call USDC micropayment
- —Integrating pay-per-use API calls into autonomous agents on Base network
- —Testing x402 protocol payment flows with low-cost endpoints
Fit
Best for
- —Developers experimenting with x402 protocol integrations
- —Agents that need keyless, pay-per-call API access settled in USDC on Base
- —Low-volume consumers who prefer per-request pricing over subscriptions
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume production workloads where $0.02/request adds up significantly
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/trades/135 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no documentation for this specific endpoint's request/response schema, no OpenAPI spec, and the docs pages are empty. The trades/135 path is not listed among the site's advertised endpoints, making its actual functionality unknown.
Warnings
- —The /api/v1/trades/135 endpoint is not listed among the site's publicly documented APIs — its purpose is unclear.
- —No request or response schema is available; callers cannot know what to send or what to expect back.
- —Documentation pages (/docs, /pricing, /api, /README) all render only a 'Connect wallet' prompt with no useful content.
- —The endpoint path includes a numeric ID (135) suggesting it may be a specific resource rather than a general-purpose API.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC ($0.02) on Base networkhttps://lowpaymentfee.com/api/v1/trades/135
- —The 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/trades/135
- —The site offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com