Pay-per-request API platform on Base network via x402 — $0.02/call in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys, accounts, or rate limits are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/carts/23` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this equals $0.02 per call, consistent with the site's advertised pricing. The payment scheme is "exact" with a 300-second timeout, payable to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3.
The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — all at the same $0.02 price point. However, documentation beyond the landing page is essentially empty (all doc/pricing/API pages just show "Connect wallet"), so the actual request/response schemas for individual endpoints are unknown. The `/api/v1/carts/23` endpoint specifically lacks any documented input or output schema beyond accepting HTTP POST and returning application/json.
Capabilities
Use cases
- —Agents needing on-demand API access without pre-registration or API keys
- —Programmatic access to utility or data endpoints with crypto micropayments
- —Testing x402 payment flows on Base network
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go API access
- —AI agents with USDC on Base that need ad-hoc endpoint calls
- —Projects exploring x402 protocol integration
Not for
- —Users needing detailed API documentation or guaranteed SLAs
- —High-volume consumers who need bulk pricing or subscription discounts
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/carts/23 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, there is no documentation, no OpenAPI schema, no request/response examples, and the purpose of the specific /api/v1/carts/23 endpoint is unclear beyond the generic label 'Premium API Access'. All doc pages are empty stubs.
Warnings
- —No API documentation available — all doc pages return only 'Connect wallet' with no content
- —The specific endpoint /api/v1/carts/23 has no documented input or output schema; its actual functionality is unknown
- —No OpenAPI spec or machine-readable schema is published
- —The 'carts/23' path suggests a specific resource ID rather than a general-purpose endpoint
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/carts/23
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com