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 with a signed USDC transfer, and the server fulfills the request upon verification.
The specific endpoint at `/api/v1/transactions/235` is listed as "Premium API Access" and accepts POST requests. Its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (asset 0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment is directed to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The broader platform advertises four categories of APIs: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). 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 are no OpenAPI specs, no request/response schemas, and no usage examples available from the crawled content. The actual behavior and response format of this specific transactions endpoint is unknown.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto quotes, gas estimates, and exchange rates on a per-call basis
- —Running geocoding or data validation utilities with instant USDC micropayments
- —Exporting analytics data or generating reports via pay-as-you-go endpoints
Fit
Best for
- —Developers who want zero-signup, pay-per-call API access
- —Agents and bots that can settle payments via x402 on Base
- —Projects needing low-cost micropayment-gated endpoints without rate limits
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —Applications requiring high-throughput bulk access at volume-discounted pricing
- —Teams that cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/235 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The purpose of this specific '/transactions/235' endpoint is unclear beyond the generic 'Premium API Access' label.
Warnings
- —No OpenAPI or schema documentation available — all docs/pricing/README pages return only 'Connect wallet'
- —The specific purpose and expected input/output of /api/v1/transactions/235 is undocumented
- —No request or response examples could be obtained
- —The broad API catalog is advertised but individual endpoint behavior is unverifiable
Citations
- —Platform advertises $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge shows maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with 300s timeouthttps://lowpaymentfee.com/api/v1/transactions/235
- —Docs, API, pricing, and README pages all render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs