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/313` 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 endpoint being listed here (`/api/v1/transactions/313`) is labeled generically as "Premium API Access" and does not appear in the site's public catalog, so its exact functionality is unclear.
Payments settle on Base via USDC (contract 0x8335…2913) to address 0x1A2B…85F3. The x402 challenge specifies version 1 with the "exact" scheme and a 300-second timeout. No OpenAPI schema, detailed documentation, or example request/response bodies were found in the crawl — the docs, pricing, and API pages all rendered only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Programmatic access to data analytics, AI inference, finance, or utility endpoints with per-call USDC micropayments
- —Agent-driven workflows that need keyless, on-demand API access settled on Base
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers or agents wanting keyless, pay-as-you-go API access
- —x402 protocol experimentation on Base with USDC
- —Low-cost per-request micropayment workflows
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-throughput production workloads where per-call crypto settlement adds latency
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/313 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base). However, the specific endpoint's purpose is unknown — it doesn't appear in the site catalog, no request/response schema is available, and all documentation pages rendered only 'Connect wallet' with no useful content. This is effectively a stub listing.
Warnings
- —The endpoint /api/v1/transactions/313 is not listed in the site's public API catalog; its actual functionality is unknown.
- —No OpenAPI spec, request schema, or response schema was found anywhere in the crawl.
- —All documentation pages (docs, pricing, API, README) returned only 'Connect wallet' with no substantive content.
- —Without knowing what this endpoint actually does, callers cannot form valid request bodies.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC ($0.02) on Base network.https://lowpaymentfee.com/api/v1/transactions/313
- —The platform lists endpoints at $0.02/request with no API keys, no rate limits, and instant access.https://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base.https://lowpaymentfee.com/api/v1/transactions/313
- —Categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure.https://lowpaymentfee.com