Pay-per-request API platform on Base (USDC) via x402 — $0.02/call, 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/172` is listed as "Premium API Access" and costs up to $0.02 per request (maxAmountRequired of 20,000 base units of USDC with 6 decimals = $0.02). Payment is made inline via the X-PAYMENT header — no API keys, accounts, or rate limits are required.
The broader platform advertises multiple API categories including 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 priced at $0.02 per request.
This particular endpoint (`/api/v1/inbox/172`) is labeled generically as "Premium API Access" and does not appear in the main category listings on the homepage. Its exact functionality is unclear — it accepts POST requests and returns `application/json`, but no input schema, documentation, or example responses are available. The platform's /api, /pricing, and /README pages all resolve to a minimal "Connect wallet" prompt with no additional documentation.
Capabilities
Use cases
- —Accessing premium API functionality with per-call 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 payment wall
Fit
Best for
- —Developers who want zero-signup, pay-per-use API access
- —AI agents with Base USDC wallets needing on-demand endpoints
- —Users comfortable with x402 payment protocol on Base
Not for
- —Users who need detailed API documentation or schemas before integrating
- —Anyone without a Base-compatible USDC wallet
- —High-volume use cases where per-request pricing at $0.02 adds up quickly
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/172 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no input/output schema, no examples, and the specific purpose of /api/v1/inbox/172 is undefined. The /api, /pricing, and /README pages are all empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —No documentation available for this specific endpoint — its purpose and expected input/output are unknown
- —The endpoint path '/api/v1/inbox/172' does not appear in the platform's public API listings
- —All documentation pages (/api, /pricing, /README) resolve to a minimal 'Connect wallet' page with no content
- —No input schema or example responses are provided anywhere
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/172
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/inbox/172
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Multiple API categories listed: Data & Analytics, AI & ML, Finance & Web3, Infrastructurehttps://lowpaymentfee.com