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 exposes 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, settled in USDC on the Base network via the x402 protocol.
The specific endpoint `/api/v1/inbox/150` is listed as "Premium API Access" and returns a valid 402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base. Payment is made via the x402 exact scheme with no API keys or rate limits required. The platform advertises instant access with a pure pay-per-use model and no minimum commitments.
Documentation is extremely sparse — the /api, /pricing, and /README pages all resolve to a wallet-connect prompt with no additional content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material. The purpose of the `/api/v1/inbox/150` path specifically (as opposed to the other named endpoints) is unclear; it may be a messaging or notification inbox endpoint, but this is not confirmed by any available documentation.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data such as token quotes, exchange rates, and gas estimates on a per-call basis
- —Running data analytics queries and exporting data with per-request billing
- —Using utility services like geocoding, validation, and conversion without subscriptions
Fit
Best for
- —Agents or developers who want zero-signup, pay-per-use API access
- —Use cases requiring low-cost micropayments settled on Base L2
- —Projects that need diverse API capabilities (AI, finance, data, utilities) from a single provider
Not for
- —Users who need detailed API documentation, schemas, or SLAs before integrating
- —High-volume production workloads where per-request pricing may not be cost-effective compared to subscription APIs
- —Users without USDC on Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/150 \
-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, confirming it accepts USDC payments on Base at $0.02/request. However, there is no OpenAPI spec, no request/response documentation, no examples, and the specific purpose of /api/v1/inbox/150 is undocumented. The /api, /pricing, and /README pages are empty wallet-connect stubs.
Warnings
- —No API documentation, OpenAPI spec, or request/response schemas available
- —The specific endpoint /api/v1/inbox/150 ('Premium API Access') has no description beyond its title — its function is unknown
- —All secondary pages (/api, /pricing, /README) return only a wallet-connect prompt with no useful content
- —No examples of expected input or output for any endpoint
Citations
- —The platform offers 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, no minimums, settled on Base networkhttps://lowpaymentfee.com
- —The /api/v1/inbox/150 endpoint returns a 402 challenge requesting up to 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/inbox/150