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/40` is listed as "Premium API Access." The x402 challenge advertises a maximum cost of 20,000 base units of USDC (asset 0x8335…2913 on Base), which equals $0.02 per request (USDC uses 6 decimals). The payment settles to address 0x1A2B…85F3 with a 300-second timeout. The endpoint accepts POST requests and returns application/json.
The broader platform advertises additional 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). All are priced at $0.02 per request. Documentation pages exist but appear to require a wallet connection and contain no visible content beyond that prompt, so detailed request/response schemas are unavailable.
Capabilities
Use cases
- —Agents that need on-demand API access without managing API keys or subscriptions
- —Programmatic access to a bundled collection of data, AI, finance, and utility endpoints
- —Micropayment-gated API calls settled in USDC on Base L2
Fit
Best for
- —Developers or agents wanting zero-signup, pay-as-you-go API access
- —x402-compatible clients that can attach USDC payments on Base
- —Low-volume or bursty workloads where per-request pricing is economical
Not for
- —High-volume production workloads where $0.02/request adds up quickly
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —Callers without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/collections/40 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no documentation beyond a wallet-connect prompt, no example request/response payloads, and the purpose of the 'collections/40' endpoint is entirely opaque beyond the label 'Premium API Access.' This is effectively a stub listing.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all render only a 'Connect wallet' prompt with no visible content — no schemas or usage instructions available.
- —The specific purpose and input/output format of /api/v1/collections/40 is unknown; 'Premium API Access' is the only description provided.
- —No OpenAPI spec or output schema beyond the basic x402 challenge metadata.
- —Cannot verify what data or functionality this endpoint actually returns.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/collections/40
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/collections/40