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/crypto market data, and general 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/32` is listed as "Premium API Access" and accepts POST requests. The x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (token contract 0x8335…2913 on Base). Since USDC uses 6 decimals, this equals $0.02 per request, consistent with the site-wide $0.02/request pricing shown on the landing page. Payment is settled on-chain to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The provider's landing page lists roughly 16 endpoints across four categories: Data & Analytics (metrics, reports, 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). Documentation pages beyond the landing page returned only a "Connect wallet" prompt, so detailed request/response schemas, parameter descriptions, and example payloads are unavailable. The exact functionality behind the `/api/v1/collections/32` path is unclear — it may be a bundled collection endpoint or an alias, but no further documentation exists to confirm.
Capabilities
Use cases
- —Agents that need on-demand AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Fetching real-time crypto token quotes, gas estimates, or exchange rates with per-call USDC micropayments
- —Geocoding or data validation as a utility service paid per request on Base
Fit
Best for
- —AI agents with Base USDC wallets needing keyless, pay-as-you-go API access
- —Developers prototyping against multiple API categories without signup or rate limits
- —Web3-native applications that prefer on-chain settlement over traditional billing
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed API documentation, SLAs, or guaranteed uptime
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/collections/32 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response examples, and all documentation pages return only a 'Connect wallet' stub. The purpose of the specific /collections/32 endpoint is undocumented. Effectively a stub listing.
Warnings
- —No documentation available — all doc/pricing/API pages return only 'Connect wallet' with no content.
- —The exact purpose and expected input/output of /api/v1/collections/32 is unknown; 'Premium API Access' is the only description.
- —No OpenAPI spec, no request schema, no response schema provided by the provider.
- —Cannot verify what data or service is actually returned behind the paywall.
Citations
- —The site lists ~16 endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories, all at $0.02/requesthttps://lowpaymentfee.com
- —Pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with 300s timeouthttps://lowpaymentfee.com/api/v1/collections/32