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 at `/api/v1/transactions/328` 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 listed at the same $0.02/request price point and settle in USDC on Base.
Documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material. The specific functionality behind the `/api/v1/transactions/328` endpoint is unclear beyond its "Premium API Access" label.
Capabilities
Use cases
- —Accessing data analytics and reports on a per-request basis without subscription
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) with per-call USDC payments
- —Fetching financial data like exchange rates, token quotes, and gas estimates
- —Geocoding and data conversion utilities paid per use
Fit
Best for
- —Developers who want API access without managing API keys or subscriptions
- —Agents and bots that can settle payments programmatically via x402 on Base
- —Low-volume or sporadic API consumers who prefer pay-as-you-go pricing
Not for
- —High-volume production workloads needing SLAs and guaranteed uptime
- —Users who need detailed API documentation or response schema guarantees before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/328 \
-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 OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no clarity on what 'Premium API Access' at /api/v1/transactions/328 actually returns. This is effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — request and response formats are unknown
- —The /docs, /pricing, /api, and /README pages all render only 'Connect wallet' with no technical content
- —The specific functionality of /api/v1/transactions/328 ('Premium API Access') is not described anywhere
- —No examples of successful responses are available
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/328
- —The platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories, all at $0.02/requesthttps://lowpaymentfee.com
- —The platform advertises no API keys, no rate limits, instant access, and Base network settlementhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/328