Pay-per-request API platform on Base (USDC) via x402 — $0.02/call, no API keys required.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to gate access to a variety of endpoints. The specific endpoint at `/api/v1/carts/26` is listed as "Premium API Access" and accepts payment in USDC on the Base network. The x402 challenge indicates a maximum amount of 20,000 base units of USDC (6 decimals), which equals $0.02 per request. No API keys, rate limits, or subscriptions are required — each call is paid individually via an on-chain USDC micropayment.
The broader platform advertises 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 the same $0.02/request price point.
However, the specific `/api/v1/carts/26` endpoint lacks detailed documentation about what it actually returns. The crawled docs, pricing, and API pages all rendered only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description beyond the generic "Premium API Access" label. The endpoint is live (returns a valid 402 challenge), but its actual functionality is unclear from available materials.
Capabilities
Use cases
- —Accessing premium API data with per-request USDC micropayments on Base
- —Agent-driven workflows that need keyless, on-demand API access
- —Programmatic purchasing of API responses without subscriptions
Fit
Best for
- —Developers who want to pay per call without API key management
- —AI agents with x402-compatible wallets on Base
- —Users who need low-cost, commitment-free API access
Not for
- —Users who need detailed API documentation or guaranteed SLAs before purchasing
- —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/carts/26 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no documentation, no OpenAPI schema, no request/response examples, and the actual functionality of /api/v1/carts/26 is completely undocumented. The docs/pricing/API pages all render only 'Connect wallet' with no useful content.
Warnings
- —The actual functionality of /api/v1/carts/26 ('Premium API Access') is not documented anywhere in the crawled material
- —No OpenAPI schema or request/response examples are available
- —Documentation pages (/docs, /api, /pricing, /README) all render only 'Connect wallet' with no substantive content
- —The endpoint path '/carts/26' suggests a shopping-cart or e-commerce resource but no details confirm this
Citations
- —The x402 challenge specifies maxAmountRequired of 20000 base units of USDC (USD Coin) on Base networkhttps://lowpaymentfee.com/api/v1/carts/26
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/carts/26
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com