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 utility services. 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/22` is listed as "Premium API Access" and accepts POST requests. The x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (contract 0x8335…2913 on Base). Since USDC uses 6 decimals, this equals $0.02 per request, consistent with the site-wide pricing displayed on the landing page. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The provider's landing page lists 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" stub, so detailed request/response schemas, parameter descriptions, and example payloads are unavailable. The `/api/v1/collections/22` path does not map obviously to any of the individually listed endpoints, so it may be a bundle or aggregate access point — this is unclear from available material.
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 USDC micropayments
- —Geocoding or data validation utilities accessible to autonomous agents via x402 payment headers
- —Exporting analytics data or generating reports without subscription commitments
Fit
Best for
- —AI agents and bots that can sign x402 USDC payments on Base
- —Developers wanting zero-signup, pay-as-you-go access to common utility APIs
- —Low-volume or sporadic callers who don't want monthly subscriptions
Not for
- —High-volume production workloads needing bulk pricing or SLAs
- —Users without a Base-network USDC wallet or x402-compatible client
- —Anyone requiring detailed API documentation or guaranteed uptime commitments
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/collections/22 \
-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/request in USDC on Base). However, documentation pages are empty stubs ('Connect wallet'), there is no OpenAPI schema, no request/response examples, and the specific purpose of /api/v1/collections/22 is ambiguous. This is effectively a stub listing with confirmed liveness but very sparse detail.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all return only 'Connect wallet' with no usable content.
- —The endpoint path /api/v1/collections/22 does not match any of the 16 individually listed endpoints — its exact function is unclear.
- —No OpenAPI spec, no request/response schema, and no example payloads are available.
- —No SLA, rate-limit, or uptime guarantees are documented.
Citations
- —The site lists 16 endpoints across four categories (Data & Analytics, AI & ML, Finance & Web3, Infrastructure) all priced at $0.02/requesthttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/collections/22
- —Site advertises no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com