Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad set of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. Every endpoint costs $0.02 per request, paid in USDC on the Base network. The x402 protocol means there are no API keys, no sign-ups, and no rate limits — callers simply attach a payment header to each request.
The specific endpoint at `/api/v1/transactions/181` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base. Payment is made to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the exact payment scheme. The endpoint accepts POST requests and returns `application/json`.
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 — all at the same $0.02 price point. However, documentation beyond the landing page 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 functionality behind this specific `/api/v1/transactions/181` endpoint is unclear from the available information.
Capabilities
Use cases
- —Accessing premium API data without needing to register or manage API keys
- —Making one-off API calls with per-request USDC micropayments on Base
- —Agent-driven workflows that need frictionless, pay-as-you-go API access
Fit
Best for
- —Developers who want zero-signup, pay-per-use API access
- —AI agents that can settle payments via x402 on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume callers who would benefit from bulk pricing or subscriptions
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/181 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC payments on Base at $0.02/request. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page, and no examples. The actual functionality of the /api/v1/transactions/181 endpoint is undocumented and unclear. This is effectively a stub listing.
Warnings
- —No OpenAPI spec or machine-readable schema available
- —Documentation pages (/docs, /api, /pricing, /README) all render only 'Connect wallet' with no technical content
- —The specific functionality of /api/v1/transactions/181 ('Premium API Access') is not described anywhere in the crawled material
- —No request body schema or response schema documented — callers cannot know what to send or what to expect back
- —The platform lists many endpoint categories (AI, finance, analytics, etc.) but provides no evidence of actual underlying functionality
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 requests maxAmountRequired of 20000 base units of USDC (0.02 USD) on Basehttps://lowpaymentfee.com/api/v1/transactions/181
- —Payment address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 and asset is USDC at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/181
- —Platform advertises endpoints for analytics, AI/ML, finance/Web3, and infrastructure utilitieshttps://lowpaymentfee.com