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 infrastructure 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/1` is listed as "Premium API Access" and returns an x402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base. The payment is settled to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the "exact" scheme with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.
The broader platform advertises four categories of APIs: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure (geocoding, validation, conversion, generation). All share the same $0.02 pricing. No OpenAPI schema, detailed documentation, or example request/response payloads were found during crawling — the docs, pricing, and README pages all returned only a "Connect wallet" prompt with no further content.
Capabilities
Use cases
- —Running sentiment analysis or text summarization without managing API keys or subscriptions
- —Fetching real-time crypto token quotes, gas estimates, or exchange rates on a per-call basis
- —Exporting data or generating analytics reports with instant pay-per-use billing
- —Geocoding addresses or validating data through utility endpoints
Fit
Best for
- —Agents or bots that need keyless, pay-per-call API access
- —Developers wanting low-friction access to AI inference endpoints
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads needing guaranteed SLAs and detailed documentation
- —Users who cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/messages/1 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{"message": "Hello"}'Example
Request
{
"message": "Hello"
}Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no OpenAPI schema, no documentation beyond a landing page listing, no example requests or responses, and the docs/pricing/README pages are gated behind a wallet connection. The actual behavior of /api/v1/messages/1 is unclear — its name and purpose are not documented.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The /api, /pricing, and /README pages return only a 'Connect wallet' prompt with no useful content
- —The specific purpose and expected input/output of /api/v1/messages/1 ('Premium API Access') is undocumented — request/response examples are inferred
- —The broader API catalog (AI, analytics, finance, utils) is advertised but none of those endpoints were individually probed
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/messages/1 requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/messages/1
- —The platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com