Pay-per-call API platform on Base (USDC) covering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API marketplace that offers a broad set of endpoints spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. Every endpoint is priced at $0.02 per request, settled in USDC on the Base network. There are no API keys, no rate limits, and no minimum commitments — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/keys/53` is listed as "Premium API Access" and accepts POST requests. Its x402 challenge advertises a maximum amount of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment is settled to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The broader platform advertises 16+ endpoints organized into 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 (geocoding, validation, conversion, generation). All share the same $0.02 flat pricing. No OpenAPI schema, detailed input/output documentation, or usage examples were found in the crawl, so the exact request and response formats for each endpoint remain unclear.
Capabilities
Use cases
- —Querying real-time financial data (prices, exchange rates, gas estimates) without managing API keys
- —Running AI inference tasks (sentiment analysis, summarization, classification, embeddings) on a pay-per-call basis
- —Performing utility operations like geocoding, data validation, and format conversion with instant access
- —Exporting analytics data and generating insights reports via simple HTTP POST calls
Fit
Best for
- —Developers who want instant, keyless API access with crypto micropayments
- —AI agents that need to autonomously purchase API calls via x402
- —Projects on the Base ecosystem looking for USDC-settled utility endpoints
Not for
- —Users who need high-volume bulk pricing or subscription discounts
- —Applications requiring detailed SLA guarantees or enterprise support
- —Callers who cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/53 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no documentation of request/response formats, no usage examples, and the /api, /pricing, and /README pages all returned only a 'Connect wallet' stub. The specific purpose of the `/api/v1/keys/53` endpoint beyond 'Premium API Access' is unknown.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —No request/response examples or field-level documentation found
- —The purpose of /api/v1/keys/53 specifically (vs. other endpoints) is unclear — 'Premium API Access' is a generic label
- —Documentation pages (/api, /pricing, /README) returned no useful content beyond 'Connect wallet'
Citations
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/keys/53 advertises maxAmountRequired of 20000 base units of USDC (USD Coin) on Base with a 300-second timeouthttps://lowpaymentfee.com/api/v1/keys/53
- —The platform offers 16+ endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com