Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint at /api/v1/payments/381 is labeled "Premium API Access" and charges up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or subscriptions are required — each request is settled individually via an on-chain USDC payment.
The broader platform advertises multiple API categories including 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 utilities (geocoding, validation, conversion, generation). All endpoints are listed at the same $0.02/request price point. However, the specific functionality behind the /api/v1/payments/381 endpoint is not documented beyond its "Premium API Access" label.
Payments are made to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 using USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base. The endpoint accepts POST requests and returns application/json. The x402 challenge was successfully captured, confirming the endpoint is live. Documentation pages (docs, pricing, README) all returned minimal content (just a "Connect wallet" prompt), so detailed request/response schemas are unavailable.
Capabilities
Use cases
- —Accessing premium API functionality with per-request USDC micropayments on Base
- —Agent-driven workflows that need keyless, on-demand API access
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers exploring x402 pay-per-call patterns
- —AI agents needing frictionless API access without pre-registration
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/381 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no documentation of what the endpoint actually returns, no request/response schema, and no OpenAPI spec. The docs, pricing, and README pages are all empty beyond a wallet-connect prompt. The specific purpose of /api/v1/payments/381 is unknown beyond its generic label.
Warnings
- —No request or response schema available — the actual functionality of /api/v1/payments/381 is undocumented
- —All documentation pages (docs, pricing, README) return only a 'Connect wallet' prompt with no useful content
- —The platform lists many API categories (AI, finance, analytics, etc.) but provides no evidence these endpoints return real data
- —Cannot verify what 'Premium API Access' actually provides
Citations
- —Endpoint returns 402 with x402 challenge advertising USDC on Base at maxAmountRequired 20000https://lowpaymentfee.com/api/v1/payments/381
- —Platform lists $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/payments/381
- —Platform advertises Data & Analytics, AI & ML, Finance & Web3, and Infrastructure API categorieshttps://lowpaymentfee.com