Pay-per-call API platform on Base network via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are paid per-request at $0.02 using USDC on the Base network, with no API keys, rate limits, or upfront commitments required. Payment is handled via the x402 protocol: callers include an X-PAYMENT header to settle each request on-chain.
The specific endpoint at `/api/v1/transactions/150` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USDC, i.e. $0.02) on Base. The platform advertises 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).
Documentation is extremely sparse — the /docs, /api, /pricing, 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 exact functionality of the `/api/v1/transactions/150` endpoint specifically is unclear; the path suggests a transaction lookup by ID but this is not confirmed by any documentation.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto prices, gas estimates, and exchange rates on a per-call basis
- —Running data analytics queries and exporting data with pay-as-you-go pricing
- —Geocoding, validation, and conversion utilities paid per request via x402
Fit
Best for
- —Developers who want instant API access without signup or API key provisioning
- —Agent-based workflows that can settle payments on Base via x402
- —Low-volume or bursty usage patterns where per-request pricing is more economical than subscriptions
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed API documentation, SDKs, or guaranteed SLAs
- —Teams without a Base-compatible USDC wallet for payment
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/150 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base). However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schemas, no examples, and the specific purpose of /api/v1/transactions/150 is ambiguous. This is effectively a stub listing.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all render only 'Connect wallet' with no usable content
- —No OpenAPI or schema documentation available for any endpoint
- —The specific function of /api/v1/transactions/150 is unclear — the path suggests a transaction lookup but this is unconfirmed
- —No request body schema or response schema is documented anywhere
- —The breadth of advertised endpoints (AI, finance, analytics, utilities) is unusual for a single platform at uniform $0.02 pricing — actual functionality is unverified
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —Payment via USDC on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/150
- —Categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —Documentation pages render only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs