Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are priced at $0.02 per request, settled in USDC on the Base network. The x402 protocol means no API keys, no accounts, and no rate limits — callers simply attach a payment header to each request.
The specific endpoint at `/api/v1/payments/376` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USDC, i.e., $0.02) on Base. The payment scheme is "exact" with a 300-second timeout. The asset is the canonical Base USDC contract (0x8335…2913).
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 sub-pages just show "Connect wallet"), so the actual behavior, input schemas, and response formats for individual endpoints are undocumented. This endpoint's specific functionality behind the "Premium API Access" label is unclear from available materials.
Capabilities
Use cases
- —Accessing paid API endpoints without creating accounts or managing API keys
- —Making one-off API calls with per-request USDC micropayments on Base
- —Agent-driven workflows that need instant, permissionless API access
Fit
Best for
- —Developers who want zero-friction, keyless API access
- —AI agents that can settle x402 payments autonomously
- —Users already holding USDC on Base who want low-cost API calls
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Anyone without a Base-compatible wallet or USDC holdings
- —High-volume consumers who prefer subscription-based pricing
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/376 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, documentation is effectively nonexistent — every sub-page returns only "Connect wallet." The specific functionality behind "Premium API Access" at /api/v1/payments/376 is undocumented, there is no OpenAPI schema, no input/output examples, and no description of what data or service is actually returned after payment.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) are all empty — only showing 'Connect wallet'
- —The specific functionality of /api/v1/payments/376 ('Premium API Access') is not described anywhere
- —No OpenAPI spec, no input schema, and no example responses are available
- —The broad catalog of endpoints listed on the homepage cannot be independently verified for functionality
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 (0.02 USD) on Base with 300-second timeouthttps://lowpaymentfee.com/api/v1/payments/376
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/payments/376
- —Platform offers endpoints across data/analytics, AI/ML, finance/Web3, and infrastructure categorieshttps://lowpaymentfee.com