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/214` 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 $0.02 per request. However, the specific `/api/v1/transactions/214` endpoint does not clearly map to any of these advertised categories, and its actual functionality is not documented beyond the generic "Premium API Access" label.
Payments settle on Base via USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3`. The x402 challenge specifies a 300-second timeout. Documentation pages (docs, pricing, README) all returned only a "Connect wallet" prompt with no substantive content, so the actual request/response schema for this endpoint is unknown.
Capabilities
Use cases
- —Programmatic access to premium API endpoints without traditional API key management
- —Agent-driven workflows that need on-demand paid API calls settled in USDC on Base
- —Exploring x402 protocol integration for pay-per-request microservices
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that can settle USDC payments on Base L2
- —Use cases requiring keyless, pay-as-you-go API access
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Anyone without a Base-compatible USDC wallet
- —Production workloads requiring well-documented request/response schemas
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/214 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is no documentation of what the endpoint actually does, no request/response schema, and the docs/pricing/README pages are all empty (just 'Connect wallet'). The specific endpoint path (/api/v1/transactions/214) doesn't match any of the advertised API categories, making its purpose unclear.
Warnings
- —The endpoint path /api/v1/transactions/214 does not correspond to any of the documented API categories on the landing page — its actual functionality is unknown.
- —All documentation pages (docs, pricing, README) returned only 'Connect wallet' with no substantive content.
- —No request body schema or response schema is documented; callers cannot know what to send or what to expect back.
- —The platform lists many endpoint categories but it is unclear whether they are all functional or placeholders.
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/214
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/214
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages returned only 'Connect wallet' with no substantive contenthttps://lowpaymentfee.com/docs