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. Every endpoint is priced at $0.02 per request, settled in USDC on the Base network via the x402 payment protocol. There are no API keys, no rate limits, and no minimum commitments — callers simply attach an X-PAYMENT header with a valid payment proof to access any endpoint.
The specific endpoint at `/api/v1/transactions/79` is listed as "Premium API Access" and returns `application/json`. Its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The endpoint accepts POST requests and is discoverable. The broader platform also exposes 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 is extremely sparse: the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further technical detail. No OpenAPI spec, request/response schemas, or usage examples are provided, so the actual behavior and data returned by each endpoint remain unclear.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without API keys
- —Fetching real-time crypto quotes, gas estimates, and exchange rates on a per-call basis
- —Geocoding and data validation as lightweight utility calls
- —Exporting data or generating analytics reports with per-request billing
Fit
Best for
- —Agents or bots that need keyless, pay-as-you-go API access
- —Developers experimenting with x402 protocol integrations on Base
- —Low-volume or bursty workloads where subscription pricing is wasteful
Not for
- —High-volume production workloads needing SLAs and guaranteed uptime
- —Users who need detailed API documentation or response schema guarantees before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/79 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The actual functionality behind 'Premium API Access' and the /transactions/79 path is unexplained.
Warnings
- —No OpenAPI spec or machine-readable schema available
- —All documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet' with no content
- —The specific purpose of /api/v1/transactions/79 ('Premium API Access') is not documented — unclear what data it returns
- —No request body schema or response schema provided; integration requires trial and error
Citations
- —Endpoint returns 402 with x402 challenge advertising 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/79
- —Platform lists endpoints across data, AI, finance, and utility categories all at $0.02/requesthttps://lowpaymentfee.com
- —No API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with 6 decimalshttps://lowpaymentfee.com/api/v1/transactions/79