Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data & analytics, AI & machine learning, finance & Web3, and infrastructure utility categories. All endpoints are priced at $0.02 per request, paid in USDC on the Base network with no API keys, rate limits, or commitments required.
The specific endpoint at `/api/v1/transactions/43` is labeled "Premium API Access" and returns an x402 challenge requesting payment of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme, settling to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point. However, documentation pages (docs, pricing, README) returned only a "Connect wallet" prompt with no substantive content, so the actual functionality behind each endpoint is unverified. The specific behavior of the `/api/v1/transactions/43` endpoint is not documented beyond its title.
Capabilities
Use cases
- —Programmatic access to utility APIs without needing API key registration
- —Agent-driven workflows that pay per call using USDC on Base
- —Exploring x402 payment protocol integration patterns
Fit
Best for
- —Developers experimenting with x402 pay-per-call protocols
- —AI agents that need keyless, on-demand API access
- —Users who want to avoid subscription commitments for occasional API calls
Not for
- —Production workloads requiring documented SLAs and detailed API schemas
- —Users without a Base-network USDC wallet
- —High-volume use cases where per-request pricing may add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/43 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but documentation pages are empty (only 'Connect wallet'). There is no OpenAPI schema, no request/response examples, and no description of what '/api/v1/transactions/43' actually returns. The platform lists many endpoints but provides no verifiable detail about any of them.
Warnings
- —Documentation pages (/docs, /pricing, /README) contain no substantive content — only 'Connect wallet' prompts.
- —The specific functionality of /api/v1/transactions/43 ('Premium API Access') is completely undocumented.
- —No OpenAPI spec, request schema, or response schema is available for any endpoint.
- —The broad range of advertised capabilities (AI, finance, geocoding, etc.) cannot be verified from available material.
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/transactions/43
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transactions/43
- —Platform advertises endpoints for analytics, AI, finance, and infrastructure categorieshttps://lowpaymentfee.com