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 hosts a broad collection of 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, paid in USDC on the Base network via the x402 protocol.
The specific endpoint `/api/v1/inbox/98` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals = $0.02). Payment is made via the x402 exact scheme with no API keys, no rate limits, and no upfront commitments required. The endpoint accepts HTTP POST and returns application/json.
Documentation is minimal — the site's /api, /pricing, and /README pages all resolve to a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available. The purpose of the `/api/v1/inbox/98` endpoint specifically is unclear; it does not map to any of the named endpoints on the landing page, so its actual functionality is unknown.
Capabilities
Use cases
- —Accessing data analytics and reporting endpoints without API key management
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) on a per-call basis
- —Fetching real-time financial data and crypto gas estimates
- —Using utility services like geocoding and validation with instant crypto-settled payments
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously on Base
- —Projects needing low-cost per-request pricing without subscriptions
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk pricing or rate-limited tiers
- —Anyone unable to pay with USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/98 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is no documentation, no OpenAPI spec, no request/response schema, and the specific /api/v1/inbox/98 path does not correspond to any named endpoint on the landing page. Its actual functionality is unknown.
Warnings
- —The endpoint path /api/v1/inbox/98 does not match any of the documented API endpoints on the landing page; its purpose is unclear.
- —No OpenAPI spec, request schema, or response schema is available.
- —All documentation pages (/api, /pricing, /README) return only a 'Connect wallet' prompt with no useful content.
- —No usage examples or error documentation found.
Citations
- —The site lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories, all priced at $0.02/requesthttps://lowpaymentfee.com
- —Pricing is $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/inbox/98 requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/inbox/98