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 set of endpoints across 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 receive a 402 challenge with payment details, settle in USDC, and get their response.
The specific endpoint at `/api/v1/transactions/333` is listed as "Premium API Access" and accepts POST requests. The 402 challenge shows a maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The platform also advertises sibling 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. Documentation pages (docs, pricing, README) appear to require wallet connection and contain no substantive content, so the actual request/response schemas for this endpoint are unknown.
Capabilities
Use cases
- —Accessing premium API data without traditional API key registration
- —Making one-off paid API calls settled in USDC on Base
- —Integrating pay-per-use endpoints into agent workflows via x402 protocol
Fit
Best for
- —Developers who want instant API access without signup or API keys
- —Agents and bots that can settle x402 payments autonomously on Base
- —Users comfortable paying in USDC for low-cost per-request pricing
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —Anyone without a Base-network USDC wallet or x402-compatible client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/333 \
-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 OpenAPI schema, no documentation of request/response formats, and all doc pages just show 'Connect wallet' with no content. The purpose of this specific '/transactions/333' endpoint is unclear beyond the generic 'Premium API Access' label.
Warnings
- —No request or response schema available — the actual functionality of /api/v1/transactions/333 is undocumented
- —All documentation pages (docs, pricing, README) are empty or require wallet connection, providing no useful information
- —The endpoint name 'Premium API Access' is generic and does not describe what data or service is returned
- —Cannot verify what the endpoint actually does without making a paid request
Citations
- —Endpoint returns 402 with maxAmountRequired of 20000 base units USDC on Base networkhttps://lowpaymentfee.com/api/v1/transactions/333
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant accesshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transactions/333
- —Platform offers endpoints across data analytics, AI/ML, finance/Web3, and infrastructure categorieshttps://lowpaymentfee.com