Pay-per-request API platform on Base via x402 — $0.02/call for data, AI, finance, and utility endpoints.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request 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 priced at $0.02 per request, settled in USDC on the Base network.
The specific endpoint at `/api/v1/inbox/101` is labeled "Premium API Access" and returns a valid x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0.02 USD given 6 decimals). It accepts POST requests and returns application/json. Payment is made via the x402 exact scheme to the specified wallet address on Base.
The platform advertises no API keys, no rate limits, no minimums, and instant access. Documentation pages (/docs, /pricing, /api, /README) all appear to require wallet connection and contain no substantive content in the crawl, so the actual behavior and response schemas of the various endpoints remain undocumented from the crawl material. The endpoint is live (402 challenge confirmed).
Capabilities
Use cases
- —AI agents needing on-demand sentiment analysis or text summarization without API key management
- —Fetching real-time crypto price feeds or gas estimates with per-call USDC payments
- —Running geocoding or data validation tasks with zero upfront commitment
- —Exporting analytics data or generating reports on a pay-as-you-go basis
- —Embedding generation for search or RAG pipelines via micropayment
Fit
Best for
- —Agents or developers who want keyless, pay-per-request API access
- —Low-volume or bursty workloads where subscriptions are wasteful
- —Crypto-native applications already operating on Base
Not for
- —High-volume production workloads where per-call pricing becomes expensive compared to subscription plans
- —Users who need detailed API documentation or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/101 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Example
Request
{
"url": "https://lowpaymentfee.com/api/v1/inbox/101",
"body": {},
"method": "POST",
"headers": {
"X-PAYMENT": "<x402-payment-token>",
"Content-Type": "application/json"
}
}Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no OpenAPI schema, no documentation of request/response formats, and all doc pages require wallet connection with no crawlable content. The actual functionality behind '/api/v1/inbox/101' (labeled generically as 'Premium API Access') is unclear — it doesn't map to any of the listed API categories on the homepage.
Warnings
- —The endpoint path /api/v1/inbox/101 does not match any of the documented API paths on the homepage; its actual functionality is unknown.
- —All documentation pages (/docs, /pricing, /api, /README) returned only 'Connect wallet' with no substantive content — no request/response schemas are available.
- —No OpenAPI spec or machine-readable schema was found.
- —Response format and expected request body for this specific endpoint are entirely undocumented in crawled material.
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/inbox/101
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com