Pay-per-call premium API on Base via x402 — $0.02/request in USDC, no API keys required.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. This specific endpoint (`/api/endpoint-27`) is listed as "Premium API Access" and accepts USDC payments on Base at a maximum cost of $0.02 per request (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader lowpaymentfee.com platform advertises 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 listed endpoints share the same $0.02/request pricing. However, this particular endpoint (`/api/endpoint-27`) does not correspond to any of the named endpoints on the site's landing page, so its exact functionality is unclear.
The endpoint is live and returns a valid x402 challenge (HTTP 402) with scheme "exact" on the Base network, paying to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`). The output schema indicates it accepts HTTP POST requests and is discoverable. Documentation beyond the landing page is essentially empty (all sub-pages just show "Connect wallet"), so request/response formats are unknown.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint without needing API key registration
- —Agent-driven workflows that settle per-call payments in USDC on Base
- —Testing x402 payment protocol integrations against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol on Base
- —AI agents that need keyless, pay-as-you-go API access
- —Low-volume callers who want no subscription or commitment
Not for
- —Users who need detailed API documentation or well-defined request/response schemas
- —High-volume production workloads where per-call crypto payments add latency
- —Anyone who needs to know exactly what the endpoint returns before paying
Quick start
curl -X POST https://lowpaymentfee.com/api/endpoint-27 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but /api/endpoint-27 does not match any named endpoint on the site. Documentation pages are empty ('Connect wallet' only). No request/response schema, no examples, and the actual functionality of this specific endpoint is unknown.
Warnings
- —Endpoint path /api/endpoint-27 does not correspond to any named endpoint on the landing page — its actual functionality is undocumented
- —All documentation, pricing, API, and README pages render only 'Connect wallet' with no useful content
- —No request body schema or response schema is available; callers cannot know what to send or expect back
- —The endpoint's purpose is entirely unclear beyond the generic label 'Premium API Access'
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/endpoint-27
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/endpoint-27
- —The site lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com