Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The specific path `/api/v1/inbox/41` is one of many endpoints offered by the provider, which hosts a broad catalog spanning data & analytics, AI & machine learning (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no commitments required.
The x402 challenge confirms the endpoint is live, accepting POST requests and settling payments in USDC (contract 0x8335…2913 on Base). The maxAmountRequired of 20000 base units equals $0.02 (USDC uses 6 decimals). Payments are sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The response MIME type is application/json.
Note that the specific functionality behind `/api/v1/inbox/41` is not documented on the provider's landing page — the listing title is simply "Premium API Access" with no further detail on what this particular inbox endpoint returns. The provider's site lists many other endpoints but does not mention an "inbox" category. Users should test the endpoint to determine its actual behavior before relying on it in production.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without needing API keys or subscriptions
- —Agent-driven workflows that need low-cost, on-demand API calls settled in USDC on Base
- —Testing x402 payment protocol integrations with a live, inexpensive endpoint
Fit
Best for
- —Developers exploring x402 payment-gated APIs
- —AI agents needing frictionless, key-free API access
- —Low-volume or bursty workloads where per-request pricing is preferable to subscriptions
Not for
- —Users who need clearly documented endpoint behavior — the inbox/41 path is undocumented
- —High-volume production use cases where the per-call cost model may not be optimal
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/41 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but the specific endpoint /api/v1/inbox/41 is completely undocumented — no schema, no examples, no description of what it actually does. The provider's landing page lists many other endpoints but not this one. Effectively a stub listing.
Warnings
- —The /api/v1/inbox/41 path is not listed or documented on the provider's landing page — its actual functionality is unknown.
- —No OpenAPI schema, request/response examples, or detailed documentation available for this endpoint.
- —The provider's /api, /pricing, and /README pages all returned only a 'Connect wallet' prompt with no useful content.
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units in USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/inbox/41
- —Provider offers endpoints across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com