x402-gated API collection on Base — pay $0.02 per request in USDC, no keys required.
What it does
lowpaymentfee.com hosts a suite of x402-protocol pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities. Every endpoint is gated by the x402 payment challenge: callers attach a USDC payment on the Base network in the X-PAYMENT header and receive the response immediately — no API keys, no accounts, no rate limits.
The specific endpoint at `/api/v1/collections/47` is listed as "Premium API Access" and accepts POST requests. The x402 challenge advertises a maximum amount of 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals), which equals $0.02 per request. The payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The broader platform advertises additional 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 (geocoding, validation, conversion, generation). All are priced at $0.02 per request. Documentation pages exist but appear to require a wallet connection to view, so detailed request/response schemas are not available from the crawl.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Fetching real-time crypto gas estimates or token price quotes with per-call USDC payment
- —Running geocoding or data validation as a utility service from an autonomous agent
- —Exporting analytics data or generating reports on a pay-as-you-go basis
Fit
Best for
- —AI agents with Base USDC wallets that need frictionless, keyless API access
- —Developers prototyping multi-service workflows without signing up for multiple providers
- —Low-volume or bursty workloads where $0.02/request flat pricing is cost-effective
Not for
- —High-volume production workloads where per-request crypto payment overhead is impractical
- —Users without a Base-network USDC wallet or x402-compatible client
- —Applications requiring detailed SLAs, guaranteed uptime, or enterprise support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/collections/47 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint works and pricing is clear ($0.02 USDC on Base). However, no OpenAPI schema, no request/response examples, and all documentation pages behind a wallet-connect gate yield no usable content. The actual functionality behind 'collections/47' is opaque — 'Premium API Access' is a generic label with no schema.
Warnings
- —Documentation pages (/docs, /pricing, /api, /README) all render only 'Connect wallet' — no public docs available without wallet connection.
- —The specific purpose of /api/v1/collections/47 ('Premium API Access') is unclear; no input/output schema is documented.
- —No OpenAPI spec or structured schema was found for any endpoint.
- —Platform appears to be a relatively new or small operation — no robots.txt, no agents.txt, minimal public information.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/collections/47
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/collections/47
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limitshttps://lowpaymentfee.com
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com