Pay-per-call API platform on Base (USDC) covering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of endpoints spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. All endpoints are paid per-request using USDC on the Base network via the x402 protocol — no API keys, no rate limits, and no subscriptions required.
The specific endpoint at `/api/v1/transactions/157` is listed as "Premium API Access" and accepts POST requests. Its x402 challenge advertises a maximum cost of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per call (USDC uses 6 decimals). The platform's landing page confirms a flat $0.02/request pricing model across all listed endpoints.
The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation. However, documentation pages (docs, pricing, README) returned only a "Connect wallet" prompt with no substantive content, so the actual behavior and response schemas of these endpoints remain undocumented. The specific functionality behind the `/api/v1/transactions/157` path is unclear — the generic "Premium API Access" label does not describe what data or service it returns.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data (prices, exchange rates, gas estimates) with per-call USDC payments
- —Running utility operations (geocoding, validation, conversion) on a pay-as-you-go basis
- —Integrating agent-purchasable endpoints into autonomous workflows via x402
Fit
Best for
- —Developers wanting zero-commitment, pay-per-use API access settled in USDC on Base
- —AI agents that need to autonomously purchase API calls without pre-provisioned keys
- —Projects needing a low-friction entry point to multiple API categories at a flat $0.02/call
Not for
- —Users who need detailed API documentation, response schemas, or guaranteed SLAs
- —High-volume production workloads where $0.02/call adds up and bulk pricing is preferred
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/157 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Example
Request
{
"url": "https://lowpaymentfee.com/api/v1/transactions/157",
"body": {},
"method": "POST",
"headers": {
"X-PAYMENT": "<x402-payment-header>",
"Content-Type": "application/json"
}
}Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02/call in USDC on Base). However, there is no documentation, no response schema, no examples, and the specific purpose of /api/v1/transactions/157 is entirely unclear. All doc/pricing/README pages returned only 'Connect wallet' with no content.
Warnings
- —The specific functionality of /api/v1/transactions/157 ('Premium API Access') is not documented anywhere — unclear what it returns.
- —All documentation pages (/docs, /pricing, /README, /api) returned only a 'Connect wallet' prompt with no substantive content.
- —No OpenAPI spec, no response schema, and no example responses are available.
- —The broad catalog of endpoints (AI, finance, utilities) is advertised but none are individually documented — actual capabilities are unverified.
Citations
- —Flat $0.02/request pricing 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 (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/157
- —Platform lists endpoints for analytics, AI (sentiment, summarization, classification, embeddings), finance, and utilitieshttps://lowpaymentfee.com
- —Documentation pages returned only 'Connect wallet' with no contenthttps://lowpaymentfee.com/docs