Pay-per-call API platform on Base network via x402 — $0.02/request, no API keys required.
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 utility services. All endpoints are paid per-request using USDC on the Base network at a flat rate of $0.02 per call, with no API keys, rate limits, or upfront commitments required.
The specific endpoint at `/api/v1/charges/350` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02, since USDC uses 6 decimals) on Base. Payment is made via the x402 exact scheme, settling to the specified wallet address. The endpoint accepts HTTP POST and returns `application/json`.
The broader platform advertises categories including 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). However, documentation pages beyond the landing page are essentially empty (showing only "Connect wallet"), so the actual behavior, input schemas, and response formats for individual endpoints are not documented in the crawled material.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto token quotes, gas estimates, or exchange rates via micropayment
- —Running geocoding or data validation utilities with per-call billing on Base USDC
- —Exporting analytics data or generating insights reports without subscription commitments
Fit
Best for
- —AI agents that need keyless, pay-per-use access to diverse API endpoints
- —Developers wanting to avoid API key provisioning and subscription overhead
- —Web3-native applications already operating on the Base network
Not for
- —High-volume production workloads where per-request pricing at $0.02 adds up significantly
- —Users who need detailed API documentation, input/output schemas, or SLA guarantees before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/350 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, and the landing page describes the platform's offerings and pricing. However, all documentation pages are empty stubs ('Connect wallet'), there is no OpenAPI spec, no input/output schema, no example requests or responses, and the specific purpose of the '/api/v1/charges/350' endpoint beyond 'Premium API Access' is unclear. This is effectively a stub listing.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) are all empty — only showing 'Connect wallet'
- —No OpenAPI or schema available; input parameters and response format for this endpoint are unknown
- —The specific function of /api/v1/charges/350 ('Premium API Access') is not explained — it may be a generic or placeholder endpoint
- —The platform lists many endpoint categories but without documentation it's unclear which are actually functional
Citations
- —Flat pricing of $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —Endpoint returns 402 with maxAmountRequired of 20000 base units of USDC on Base (= $0.02)https://lowpaymentfee.com/api/v1/charges/350
- —Platform offers endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/charges/350