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/258` 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/258`) 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 version 1 challenge. Payment is settled in USDC (contract 0x8335…2913) on Base to address 0x1A2B…85F3, with a 300-second timeout. No OpenAPI schema, detailed documentation, or example responses were found — the docs, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without needing API keys or subscriptions
- —Agent-driven workflows that need to pay for API calls on-chain via x402
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —AI agents that settle API costs in USDC on Base
- —Users who want zero-commitment, per-request pricing
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Anyone without a Base-network USDC wallet or x402-compatible client
- —High-volume production workloads where $0.02/request adds up quickly
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/258 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but the specific functionality behind '/api/v1/charges/258' is undocumented. No OpenAPI schema, no example requests/responses, and all doc pages return only 'Connect wallet' with no content. The generic 'Premium API Access' label provides no insight into what the endpoint actually does.
Warnings
- —The endpoint path '/api/v1/charges/258' does not correspond to any of the named endpoints on the landing page; its actual functionality is unknown.
- —All documentation pages (docs, pricing, README, api) returned only 'Connect wallet' with no substantive content.
- —No OpenAPI spec, no input/output schema, and no example responses are available.
- —The platform's advertised capabilities (AI, analytics, finance, etc.) cannot be verified from the crawl data.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/charges/258
- —USDC contract address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/charges/258
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com