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 infrastructure utilities. 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 specific endpoint at `/api/v1/transactions/240` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02 given USDC's 6 decimals) on Base.
The platform advertises categories including 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 (geocoding, validation, conversion, generation). All endpoints follow the x402 payment protocol: callers receive a 402 challenge with payment details, settle in USDC on Base, and then gain access to the response.
Documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material. The actual behavior and output of the `/api/v1/transactions/240` endpoint is unknown beyond its x402 challenge metadata.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, exchange rates, and gas estimates on a per-call basis
- —Running utility operations such as geocoding, validation, and data conversion with instant crypto-settled payments
Fit
Best for
- —Developers who want zero-signup, pay-per-use API access settled in USDC on Base
- —Agents and bots that can autonomously pay for API calls via x402 protocol
- —Projects needing a variety of lightweight API services at a flat $0.02/call rate
Not for
- —Users who need detailed API documentation, schemas, or guaranteed SLAs before integrating
- —Teams requiring high-volume bulk pricing or subscription-based access
Quick start
# x402 flow: POST to the endpoint, receive 402 challenge, pay USDC on Base, re-send with X-PAYMENT header
curl -X POST https://lowpaymentfee.com/api/v1/transactions/240 \
-H 'Content-Type: application/json'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page listing, and no examples. The actual functionality of the /api/v1/transactions/240 'Premium API Access' endpoint is entirely opaque.
Warnings
- —No OpenAPI specification or request/response schema available
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no technical content
- —The specific purpose and output of /api/v1/transactions/240 ('Premium API Access') is undocumented — it is unclear what data or service it provides
- —No usage examples or error documentation found
Citations
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/transactions/240 requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/240
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com