Pay-per-request API suite on Base via x402 — data, AI, finance, and utility endpoints at $0.02/call.
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 utility services. Every endpoint is priced at $0.02 per request, paid in USDC on the Base network with no API keys, rate limits, or upfront commitments required.
The specific endpoint listed here (`/api/v1/carts/10`) is described as "Premium API Access" and advertises a maximum cost of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is via the x402 exact scheme: callers attach an X-PAYMENT header with a signed payment to the payTo address, and the server fulfills the request upon verification. The endpoint accepts POST requests and returns application/json.
The broader platform advertises additional endpoint categories including 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 per-call price point. Documentation pages beyond the landing page appear to require wallet connection and contain no additional technical detail, so the exact request/response schemas for individual endpoints are unknown.
Capabilities
Use cases
- —Agents that need on-demand AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Fetching real-time financial data or crypto gas estimates with per-call payment
- —Running geocoding, validation, or data conversion tasks without subscription overhead
- —Exporting analytics data or generating insights reports on a pay-as-you-go basis
Fit
Best for
- —AI agents needing keyless, pay-per-use access to diverse API endpoints
- —Developers who want to avoid subscription commitments for low-volume API usage
- —Web3-native applications that can pay in USDC on Base
Not for
- —High-volume production workloads where per-call pricing at $0.02 adds up quickly
- —Users who cannot transact in USDC on the Base network
- —Applications requiring detailed SLAs, rate-limit guarantees, or enterprise support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/carts/10 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema documentation, and all doc pages beyond the landing page only show 'Connect wallet' with no content. The specific purpose of /api/v1/carts/10 is unclear — it doesn't match any of the advertised endpoint categories.
Warnings
- —The endpoint path /api/v1/carts/10 does not match any of the documented API categories on the landing page; its actual functionality is unknown.
- —Documentation, pricing, and README pages all render only 'Connect wallet' with no usable content.
- —No OpenAPI spec or request/response schemas are available for any endpoint.
- —The platform advertises many endpoint categories but none have verifiable documentation beyond the landing page listing.
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or commitmentshttps://lowpaymentfee.com
- —Payment in USDC on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/carts/10
- —Endpoint categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com