Pay-per-request API platform on Base via x402 — $0.02/call in USDC, no API keys required.
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/inbox/102` is listed as "Premium API Access" and charges up to 20,000 base units of USDC (i.e., $0.02) per request. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an x402 payment header to each POST request.
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 the same $0.02/request price point.
However, the specific endpoint being listed here (`/api/v1/inbox/102`) does not clearly map to any of the named endpoints on the landing page. Its description is simply "Premium API Access" with no further documentation on what it returns or what input it expects. The docs, pricing, and API pages all returned only a "Connect wallet" prompt with no substantive content. Without schema details or response examples, the actual functionality of this particular endpoint remains unclear.
Capabilities
Use cases
- —Accessing premium API functionality with per-request USDC micropayments on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API access
- —Programmatic access to an inbox or messaging endpoint behind a paywall
Fit
Best for
- —Developers who want to avoid API key management and subscription commitments
- —AI agents with x402-compatible wallets on Base
- —Low-volume or bursty usage patterns where per-call pricing is economical
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/102 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Example
Request
{
"url": "https://lowpaymentfee.com/api/v1/inbox/102",
"body": {},
"method": "POST",
"headers": {
"X-PAYMENT": "<x402-payment-token>",
"Content-Type": "application/json"
}
}Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge) and pricing is clear ($0.02 USDC on Base). However, the specific endpoint /api/v1/inbox/102 has no documentation, no input/output schema, no response examples, and its purpose is entirely opaque. The docs/pricing/API pages are empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —The endpoint /api/v1/inbox/102 does not appear in the provider's listed API catalog — its actual functionality is unknown.
- —All documentation pages (docs, pricing, API, README) returned only a 'Connect wallet' prompt with no substantive content.
- —No input or output schema is available; callers cannot know what to send or what to expect back.
- —The platform's broader claims (AI endpoints, finance feeds, etc.) are unverifiable from the crawled content.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/102
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/inbox/102
- —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