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/387` is listed as "Premium API Access" and returns a 402 challenge requiring payment of up to 20,000 base units of USDC (i.e., $0.02) per call. No API keys or rate limits are required; callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform advertises multiple API categories including 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 listed at the same $0.02/request price point.
However, the specific endpoint probed (`/api/v1/transactions/387`) does not clearly map to any of the documented API categories on the landing page. Its description is simply "Premium API Access" with no further documentation about what data or functionality it returns. The docs, pricing, and API pages all rendered only a "Connect wallet" prompt with no additional content, so detailed request/response schemas and usage examples are unavailable.
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
- —Testing x402 protocol payment flows on Base network
Fit
Best for
- —Developers experimenting with x402 pay-per-call patterns
- —Agents that need keyless, on-demand API access settled in USDC
- —Low-volume consumers who prefer per-request pricing over subscriptions
Not for
- —Users needing detailed API documentation or guaranteed SLAs
- —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/387 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no documentation for this specific endpoint's purpose, no request/response schema, and the docs/pricing/API pages are empty beyond a wallet-connect prompt. The endpoint path '/api/v1/transactions/387' with description 'Premium API Access' is vague and doesn't match any documented category.
Warnings
- —No documentation available for /api/v1/transactions/387 — purpose and response format are unknown
- —All secondary pages (docs, pricing, API, README) render only 'Connect wallet' with no content
- —The endpoint path suggests a specific transaction resource (ID 387) rather than a general-purpose API
- —No OpenAPI spec, no request/response schema, no usage examples available
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/transactions/387
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/387
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Multiple API categories listed: Data & Analytics, AI & ML, Finance & Web3, Infrastructurehttps://lowpaymentfee.com