Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint `/api/v1/transactions/119` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) per call. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform offers endpoints across four categories: 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). All endpoints are uniformly priced at $0.02 per request.
This particular endpoint (`/api/v1/transactions/119`) is labeled "Premium API Access" but its actual functionality is not documented beyond that label. The crawled docs, pricing, API, and README pages all returned only a "Connect wallet" prompt with no further content. Without additional documentation or response schema details, the exact data returned by this endpoint remains unclear.
Capabilities
Use cases
- —Accessing premium data or transaction information via a single micropayment
- —Integrating pay-per-use API calls into agent workflows without managing API keys
- —Programmatic access to platform services settled in USDC on Base
Fit
Best for
- —Developers wanting keyless, pay-per-call API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or response schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/119 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02/request. However, there is no documentation for what this specific endpoint returns, no OpenAPI schema, no example responses, and all doc pages render only a wallet-connect prompt. The endpoint's actual functionality behind 'Premium API Access' is entirely opaque.
Warnings
- —No documentation available — all doc/pricing/API/README pages return only 'Connect wallet' with no content
- —The endpoint name 'Premium API Access' and path '/api/v1/transactions/119' give no clear indication of what data or service is provided
- —No output schema or example response is available; integrators cannot know what to expect
- —This endpoint is not listed on the homepage's catalog of available APIs, raising questions about its purpose
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC ($0.02) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/119
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —The USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transactions/119