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 broad catalog of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. Every endpoint costs $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no commitments required. The x402 protocol handles payment inline: callers attach a signed USDC payment in the X-PAYMENT header and receive the response immediately.
The specific endpoint at `/api/v1/transactions/359` is listed as "Premium API Access" and accepts POST requests. Its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base), which equals $0.02 given USDC's 6 decimals. The payment is sent 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 is extremely thin: the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no examples available. The actual behavior and data returned by this specific transactions endpoint is unknown from the available material.
Capabilities
Use cases
- —Accessing premium API data with per-request USDC micropayments on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API access
- —Programmatic access to transaction or financial data without subscription commitments
Fit
Best for
- —Developers who want zero-signup, pay-per-call API access
- —AI agents with x402-compatible payment capabilities
- —Users already holding USDC on Base network
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who prefer subscription-based pricing over per-call payments
- —Developers without USDC on Base network or x402 client libraries
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/359 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is zero documentation on what this endpoint actually does, no request/response schemas, no examples, and the docs pages are empty. The 'Premium API Access' label is generic and uninformative.
Warnings
- —No OpenAPI spec or schema documentation available
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content
- —The purpose and behavior of /api/v1/transactions/359 is completely undocumented — 'Premium API Access' is the only description
- —No request body schema or response schema is provided; integration requires trial and error
Citations
- —The platform advertises $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge for this endpoint shows maxAmountRequired of 20000 base units of USDC on Base with a 300-second timeouthttps://lowpaymentfee.com/api/v1/transactions/359
- —USDC asset address on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/359
- —Documentation pages /docs, /api, /pricing, /README all show only 'Connect wallet'https://lowpaymentfee.com/docs