Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that provides a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/inbox/113` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys or accounts are required; callers pay via the x402 protocol by attaching an X-PAYMENT header to each POST request.
The platform advertises four categories of APIs: 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 per-request pricing with no minimums, commitments, or rate limits.
Important caveat: the specific `/api/v1/inbox/113` endpoint is not explicitly described in the site's public catalog — it may be a custom or unlisted inbox-style endpoint. The x402 challenge confirms it is live and accepts POST requests returning application/json. Beyond the generic "Premium API Access" label, no documentation, request schema, or response schema is available for this particular path.
Capabilities
Use cases
- —Accessing premium API endpoints without creating an account or managing API keys
- —Making one-off paid API calls from autonomous agents using x402 payment protocol
- —Integrating pay-as-you-go data or utility services into workflows settled on Base
Fit
Best for
- —Agents or developers wanting frictionless, keyless API access via crypto micropayments
- —Low-volume or sporadic API consumers who prefer per-call pricing over subscriptions
- —x402-compatible clients on the Base network
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk pricing or subscription plans
- —Developers without USDC on Base or unfamiliar with x402 payment flows
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/113 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and confirms pricing and network, but the specific /api/v1/inbox/113 endpoint has no documentation, no request/response schema, and no examples. The endpoint name 'Premium API Access' is entirely generic. The site's other pages returned only 'Connect wallet' with no useful content.
Warnings
- —The /api/v1/inbox/113 path does not appear in the site's public API catalog — its purpose is unknown.
- —No request or response schema is available for this endpoint.
- —Documentation pages (/api, /pricing, /README) returned no meaningful content beyond 'Connect wallet'.
- —The endpoint's actual functionality cannot be verified from available materials.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 in USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/113
- —All listed APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/inbox/113