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 `/api/v1/charges/148` is listed as "Premium API Access" and returns a 402 challenge requiring payment of up to 20,000 base units of USDC (i.e., $0.02) per call. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader lowpaymentfee.com platform offers endpoints across four categories: 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 $0.02 per request. However, the specific endpoint being listed here (`/api/v1/charges/148`) is labeled generically as "Premium API Access" and does not map directly to any of the named endpoints on the landing page, so its exact functionality is unclear.
The endpoint is live and responds with a well-formed x402 challenge. Payment settles in USDC on Base to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3`. The response MIME type is `application/json`. No OpenAPI schema, detailed documentation, or example responses were found — the docs, pricing, and API pages all render only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint with per-call USDC micropayments
- —Agent-driven workflows that need keyless, pay-as-you-go API access on Base
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that need keyless API access with crypto micropayments
- —Low-volume, on-demand API consumption without subscriptions
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume use cases where $0.02/request adds up significantly
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/148 \
-H "X-PAYMENT: <x402-payment-proof>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but the specific functionality behind '/api/v1/charges/148' is undocumented. No OpenAPI schema, no example requests/responses, and the docs pages are empty beyond a wallet-connect prompt. The endpoint path ('charges/148') doesn't match any of the named APIs on the landing page, making its purpose unclear.
Warnings
- —The endpoint path /api/v1/charges/148 does not correspond to any of the named API endpoints listed on the landing page — its actual functionality is unknown.
- —No documentation, OpenAPI spec, or example responses are available; docs/pricing/API pages only show 'Connect wallet'.
- —The broader platform lists many endpoint categories (AI, finance, analytics, etc.) but none are verified to actually return useful data.
- —Cannot confirm what data or service this specific endpoint provides beyond the generic 'Premium API Access' label.
Citations
- —The platform lists endpoints at $0.02/request with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —The x402 challenge requires up to 20,000 base units of USDC (USD Coin, 6 decimals = $0.02) on Base network.https://lowpaymentfee.com/api/v1/charges/148
- —Payment address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 and the asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 (USDC on Base).https://lowpaymentfee.com/api/v1/charges/148
- —The platform advertises categories including Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure.https://lowpaymentfee.com