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 an 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/30` 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 site's landing page confirms a flat $0.02/request pricing model across all endpoints.
The broader platform offers endpoints for metrics, reports, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point. Documentation pages beyond the landing page were largely empty (showing only "Connect wallet"), so detailed request/response schemas, parameter descriptions, and example payloads are not available. The endpoint is live and returning a valid x402 challenge.
Capabilities
Use cases
- —Agents that need 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 payment
- —Running geocoding or data validation as a utility service from an autonomous workflow
- —Exporting analytics data or generating reports with no subscription commitment
- —Web3-native applications that want to pay for API calls directly on-chain
Fit
Best for
- —AI agents and bots that can attach x402 payment headers autonomously
- —Developers who want zero-signup, pay-as-you-go API access
- —Low-volume or bursty workloads where $0.02/call is cost-effective
Not for
- —High-volume production workloads where per-call costs add up quickly
- —Users without a Base-network USDC wallet or x402-compatible client
- —Anyone needing detailed SLAs, guaranteed uptime, or enterprise support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/collections/30 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, documentation pages are effectively empty, there is no OpenAPI spec, no request/response schema, and no example payloads. The 'collections/30' path is opaque — it's unclear what this specific collection endpoint actually returns versus the individually named endpoints on the landing page.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all render only 'Connect wallet' with no usable content.
- —No OpenAPI or JSON schema available — request parameters and response format are unknown.
- —The specific purpose of /api/v1/collections/30 ('Premium API Access') is unclear; it may be a bundle or alias for other endpoints.
- —No information on uptime guarantees, error handling, or data freshness.
Citations
- —Flat $0.02 per request pricing, no API keys, no rate limits, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (6 decimals = $0.02) on Basehttps://lowpaymentfee.com/api/v1/collections/30
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/collections/30
- —Available endpoint categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com