Pay-per-call API suite on Base (USDC) covering AI, analytics, 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, paid in USDC on the Base network via the x402 protocol. There are no API keys, no rate limits, and no upfront commitments — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/messages/200` is listed as "Premium API Access" and follows the same x402 payment pattern. The 402 challenge confirms it accepts POST requests, charges up to 20,000 base units of USDC (i.e., $0.02 given USDC's 6 decimals), and settles on Base to address `0x1A2B…85F3`. 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 data generation — all at the same $0.02 price point.
Documentation is minimal: the landing page lists available endpoints and pricing, but there is no OpenAPI spec, no request/response schema documentation, and the /api, /pricing, and /README pages all resolve to a bare "Connect wallet" prompt. Without schema details or example payloads, callers will need to experiment to discover the expected input and output formats for each endpoint.
Capabilities
Use cases
- —Running one-off AI inference tasks (sentiment, summarization, classification) without managing API keys
- —Fetching real-time crypto token quotes or gas estimates from an agent workflow
- —Geocoding or data validation as part of an automated pipeline with per-call billing
- —Generating text embeddings for search or RAG without a subscription
Fit
Best for
- —Agents that need low-friction, keyless API access with crypto micropayments
- —Developers prototyping across multiple API categories (AI, finance, utilities) at uniform pricing
- —x402-compatible wallets and agent frameworks on Base
Not for
- —High-volume production workloads that need SLAs, rate-limit guarantees, or detailed documentation
- —Users who require fiat billing or cannot transact in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/messages/200 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{"message": "Hello"}'Example
Request
{
"message": "Hello"
}Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no documented request/response schemas, no example payloads, and the ancillary pages (/api, /pricing, /README) are empty. The listing is essentially a stub with pricing info only.
Warnings
- —No OpenAPI or schema documentation available — request and response formats are unknown
- —Ancillary pages (/api, /pricing, /README) return only 'Connect wallet' with no useful content
- —The specific purpose of /api/v1/messages/200 is unclear; 'Premium API Access' is a generic label
- —Example request JSON is speculative — no schema was provided by the endpoint
Citations
- —Endpoint returns HTTP 402 with x402 challenge, confirming it is live on Base with USDChttps://lowpaymentfee.com/api/v1/messages/200
- —maxAmountRequired is 20000 base units of USDC (6 decimals) = $0.02 per requesthttps://lowpaymentfee.com/api/v1/messages/200
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Available endpoint categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com