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/122` is listed as "Premium API Access" and costs up to $0.02 per request (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an x402 payment header to each request.
The platform advertises four endpoint 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 listed endpoints share the same $0.02/request pricing.
The specific purpose of the `/api/v1/inbox/122` endpoint is unclear from available documentation — it is labeled generically as "Premium API Access" and does not appear in the public catalog on the landing page. The endpoint is live and returns a valid x402 challenge with USDC on Base. No OpenAPI schema, request/response examples, or detailed documentation were found beyond the landing page listing.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, exchange rates, and gas estimates
- —Running utility operations like geocoding, validation, and data conversion on a per-call basis
- —Integrating pay-per-use data analytics and reporting into agent workflows
Fit
Best for
- —AI agents needing low-friction, keyless API access with crypto micropayments
- —Developers who want pay-as-you-go pricing without subscriptions or rate limits
- —Applications requiring diverse utility endpoints (AI, finance, geo, data) from a single provider
Not for
- —Users who need free or fiat-only payment options
- —High-volume batch processing where per-request pricing becomes expensive
- —Use cases requiring detailed SLAs, uptime guarantees, or enterprise support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/122 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but the specific purpose of /api/v1/inbox/122 is undocumented. No OpenAPI schema, request/response examples, or detailed docs exist. The landing page lists many endpoints but this specific one is absent from the catalog. Effectively a stub listing.
Warnings
- —The endpoint /api/v1/inbox/122 does not appear in the provider's public API catalog — its specific functionality is unknown.
- —No OpenAPI schema, request body format, or response examples are available.
- —Crawled /api, /pricing, and /README pages returned only 'Connect wallet' with no useful content.
- —The platform lists many endpoint categories but no documentation verifying they are functional was found.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/122
- —All listed endpoints are priced at $0.02 per request with no API keys, rate limits, or commitmentshttps://lowpaymentfee.com
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/inbox/122