Pay-per-request API platform on Base via x402 — $0.02/call for data, AI, finance, and utility endpoints.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across 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, settled in USDC on the Base network.
The specific endpoint at `/api/v1/transactions/366` is listed as "Premium API Access" and its x402 challenge advertises a maxAmountRequired of 20000 base units of USDC (0x8335…2913 on Base), which equals $0.02. Payment is made via the x402 exact scheme with no API keys or rate limits required — callers simply attach an X-PAYMENT header to each POST request.
Documentation is extremely sparse. The landing page lists available endpoints and pricing, but the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples. The actual functionality behind the `/api/v1/transactions/366` path is unclear — it does not obviously map to any of the advertised endpoint categories. Prospective users should be aware that without documentation, integrating these endpoints requires experimentation.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without API key signup
- —Fetching real-time finance data (prices, exchange rates, gas estimates) on a per-call basis
- —Running utility operations (geocoding, validation, conversion) with instant crypto-settled access
- —Prototyping agent workflows that need low-friction, pay-as-you-go API access
Fit
Best for
- —Developers wanting zero-signup, pay-per-request API access
- —AI agents that can settle x402 payments in USDC on Base
- —Projects needing low-cost micropayment-gated endpoints
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume production workloads requiring bulk pricing or rate guarantees
- —Developers without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/366 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but documentation is effectively nonexistent — /docs, /pricing, /api, and /README all show only 'Connect wallet'. No OpenAPI spec, no request/response schemas, and no examples are available. The specific endpoint path (/api/v1/transactions/366) does not clearly map to any advertised service category.
Warnings
- —Documentation pages (/docs, /pricing, /api, /README) are empty — only show 'Connect wallet'
- —No OpenAPI spec or request/response schema available
- —The endpoint path /api/v1/transactions/366 does not match any of the advertised API categories on the landing page
- —Actual functionality behind this specific endpoint is unknown — 'Premium API Access' is a generic label
- —No usage examples or integration guides found
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/366
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —Documentation pages render only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs