Pay-per-call API suite for analytics, AI, finance, and utilities — $0.02/request via x402 on Base.
What it does
lowpaymentfee.com offers a collection of x402-enabled API endpoints spanning four categories: 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 utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, paid in USDC on the Base network via the x402 protocol.
The probed endpoint `/api/v1/auth` returned a valid 402 challenge advertising a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals), which equals $0.02. Payment is made per-request with no API keys, no rate limits, and no subscription commitments. The x402 challenge specifies an "exact" payment scheme with a 300-second timeout.
Documentation is minimal — the landing page lists endpoints and prices but provides no request/response schemas, parameter descriptions, or usage examples. The `/api`, `/pricing`, and `/README` pages all resolve to a bare "Connect wallet" prompt with no additional content. Without OpenAPI specs or detailed docs, the actual behavior of each endpoint is unknown beyond the endpoint names and category descriptions shown on the homepage.
Capabilities
Use cases
- —Running sentiment analysis or text summarization without managing API keys or subscriptions
- —Fetching real-time crypto token quotes and gas estimates with per-call payment
- —Geocoding addresses or validating data via a simple pay-per-request model
- —Exporting analytics data or generating insights on demand
- —Generating text embeddings for search or recommendation pipelines
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously on Base
- —Projects needing low-cost utility endpoints without rate limits
Not for
- —Production workloads requiring documented, stable API contracts with SLAs
- —Users without USDC on the Base network or x402-compatible payment tooling
- —High-volume batch processing where per-call pricing may add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/auth \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, there is no OpenAPI spec, no request/response schemas, no parameter documentation, and no usage examples for any of the 16 listed endpoints. The actual functionality behind each endpoint is unverifiable from the available material.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —No request/response examples or parameter descriptions provided
- —The /api, /pricing, and /README pages contain no useful content beyond 'Connect wallet'
- —Actual functionality of listed endpoints (AI, analytics, finance, utils) is unverified — only endpoint names are known
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/auth specifies maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with exact scheme and 300s timeouthttps://lowpaymentfee.com/api/v1/auth
- —16 endpoints are listed across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com