Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad set of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. Every endpoint costs $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no commitments required. The x402 protocol handles payment inline: callers attach an X-PAYMENT header with a signed USDC payment, and the server fulfills the request upon verification.
The specific endpoint at `/api/v1/transactions/367` is listed as "Premium API Access" and accepts POST requests. Its x402 challenge advertises a maxAmountRequired of 20000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The platform also advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point. Documentation pages exist but appear gated behind a wallet connection, so detailed request/response schemas for individual endpoints are not publicly available. Without further documentation, the exact input parameters and response format for this specific transactions endpoint are unknown.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without API key signup
- —Fetching real-time crypto quotes, gas estimates, or exchange rates on a per-call basis
- —Running geocoding or data validation utilities with instant USDC micropayments
- —Exporting data or generating analytics reports pay-as-you-go
Fit
Best for
- —Developers who want instant API access without registration or API keys
- —Agents and bots that can settle payments programmatically via x402 on Base
- —Low-volume or bursty workloads where per-request pricing is more economical than subscriptions
Not for
- —High-volume production workloads where $0.02/request adds up quickly
- —Users without a Base-network USDC wallet or x402-compatible client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/367 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-signed-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no documented request/response format for this specific endpoint, and all doc pages beyond the landing page are gated behind wallet connection. The purpose of '/api/v1/transactions/367' is unclear beyond the generic 'Premium API Access' label.
Warnings
- —No public documentation available — all doc pages require wallet connection
- —The specific purpose and expected input/output of /api/v1/transactions/367 is undocumented
- —No OpenAPI or schema definition found for any endpoint
- —The platform lists many endpoint categories but it is unclear whether they are all functional or placeholders
Citations
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/367
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com