Pay-per-call API suite on Base (USDC) covering analytics, AI, finance, and utilities at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and general-purpose utilities. Every endpoint is priced at $0.02 per request, settled in USDC on the Base network. There are no API keys, no rate limits, and no minimum commitments — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/inbox/111` 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 given USDC's 6 decimals. The payment timeout is 300 seconds. The broader platform advertises additional 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 minimal: the landing page lists available endpoints with brief labels and prices, but there is no OpenAPI spec, no request/response schema documentation, and no usage examples. The /api, /pricing, and /README pages all resolve to a "Connect wallet" prompt with no additional content. Because of this, the actual input parameters and response formats for each endpoint are unknown and must be discovered experimentally.
Capabilities
Use cases
- —Running sentiment analysis or text summarization without managing API keys or subscriptions
- —Fetching real-time crypto token quotes or gas estimates on a per-call payment basis
- —Geocoding addresses or validating data with zero upfront commitment
- —Exporting data or generating analytics reports paid per request via USDC on Base
Fit
Best for
- —Agents or developers who want zero-signup, pay-as-you-go API access
- —Crypto-native workflows that can attach x402 payment headers
- —Low-volume or bursty workloads where per-call pricing is more economical than subscriptions
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume production workloads where $0.02/request adds up significantly
- —Teams that cannot settle payments in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/111 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, and the landing page confirms pricing and lists available endpoints. However, there is no OpenAPI spec, no request/response schema, no usage examples, and no documentation beyond endpoint names and prices. The purpose of the specific /inbox/111 endpoint is unclear.
Warnings
- —No OpenAPI spec or request/response schema available for any endpoint
- —The /api, /pricing, and /README pages contain no documentation — only a 'Connect wallet' prompt
- —The specific purpose of /api/v1/inbox/111 ('Premium API Access') is undocumented and unclear
- —No examples of expected input or output formats are provided anywhere
Citations
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/inbox/111 advertises maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/inbox/111
- —Available endpoint categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com