Pay-per-call API platform on Base with USDC payments at $0.02/request via x402.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, payable in USDC on the Base network. No API keys, rate limits, or subscriptions are required — callers simply attach an x402 payment header to each request.
The specific endpoint `/api/v1/inbox/6` is listed as "Premium API Access" and returns a 402 challenge requesting up to 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 returns `application/json`. 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 functionality behind `/api/v1/inbox/6` (and what "Premium API Access" specifically provides) is unclear.
Capabilities
Use cases
- —Accessing pay-per-call API services without subscriptions or API keys
- —Integrating USDC-based micropayments into automated agent workflows
- —Consuming data, AI, finance, or utility endpoints on a per-request basis
Fit
Best for
- —Agents or developers wanting zero-commitment, pay-as-you-go API access
- —x402-compatible clients on the Base network
- —Low-volume or sporadic API consumers who want to avoid subscriptions
Not for
- —Users needing detailed API documentation or guaranteed SLAs
- —High-volume consumers who would benefit from bulk pricing or rate-limited tiers
- —Anyone without USDC on Base or an x402-compatible payment client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/6 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is no OpenAPI spec, no request/response schema, no documentation beyond endpoint names and prices, and the purpose of '/api/v1/inbox/6' ('Premium API Access') is entirely opaque. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The specific function of /api/v1/inbox/6 ('Premium API Access') is undocumented and unclear
- —All non-root pages (/api, /pricing, /README) return only a 'Connect wallet' prompt with no useful content
- —No request body schema or response examples are available anywhere in the crawl
Citations
- —All endpoints are priced at $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/inbox/6 requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/inbox/6
- —The platform lists endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com