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 upfront commitments. The x402 protocol handles payment inline: callers attach an X-PAYMENT header to each request and the server settles on-chain before returning the response.
The specific endpoint at `/api/v1/transactions/128` is listed as "Premium API Access." Its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (asset 0x8335…2913 on Base, 6 decimals), which equals $0.02. The payment scheme is "exact" with a 300-second timeout, and the endpoint accepts POST requests. Beyond this particular path, the platform advertises roughly 16 endpoints across four categories: Data & Analytics (metrics, reports, export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure (geocoding, validation, conversion, generation).
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawl. The endpoint is confirmed live (402 challenge captured), but without schema details or sample payloads it is difficult to know what request body to send or what response to expect.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key registration
- —Fetching real-time crypto quotes, gas estimates, and exchange rates on a per-call basis
- —Running geocoding, validation, or data conversion tasks with instant USDC micropayments
- —Exporting data or pulling analytics metrics without subscription commitments
Fit
Best for
- —Developers who want zero-signup, pay-as-you-go API access
- —Agents and bots that can settle USDC payments on Base via x402
- —Users needing low-cost micropayment APIs without rate limits
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —Applications requiring high-throughput batch processing where per-call pricing is inefficient
- —Developers without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/128 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge and clear pricing ($0.02 USDC on Base). However, documentation is effectively absent — all doc pages render only 'Connect wallet' with no schemas, examples, or descriptions of what the endpoint actually returns. The specific path /api/v1/transactions/128 has no documented purpose beyond the generic label 'Premium API Access.'
Warnings
- —Documentation pages (/docs, /pricing, /api, /README) are all empty beyond a 'Connect wallet' prompt — no usable docs available.
- —No OpenAPI spec or request/response schema is published.
- —The purpose of /api/v1/transactions/128 specifically is unclear; 'Premium API Access' is a generic label.
- —The broad catalog of 16+ endpoints is advertised on the landing page but none have documented input/output contracts.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/128
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages render only a 'Connect wallet' prompt with no further contenthttps://lowpaymentfee.com/docs