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/125` 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 rate limits are advertised; callers pay per request via the x402 protocol's X-PAYMENT header.
The wider 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. However, the specific functionality behind the `/api/v1/inbox/125` path is not documented — the name "Premium API Access" is generic and no input/output schema beyond `POST application/json` is provided.
The endpoint is live and returns a valid x402 challenge (HTTP 402) with scheme "exact" on the Base network, paying to address `0x1A2B...85F3` using USDC (`0x8335...2913`). The timeout is 300 seconds. Because no detailed documentation, OpenAPI spec, or example payloads are available for this specific endpoint, its actual behavior remains unclear.
Capabilities
Use cases
- —Paying per-request for data analytics or AI inference without managing API keys
- —Integrating USDC-settled micropayments into agent workflows on Base
- —Accessing utility endpoints (geocoding, validation, conversion) with instant crypto payment
Fit
Best for
- —Agents or developers who want keyless, pay-per-call API access
- —Crypto-native applications already operating on the Base network
- —Low-volume or bursty workloads where subscription pricing is wasteful
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk/subscription pricing
- —Developers without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/125 \
-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 path /api/v1/inbox/125 has no documentation, no input/output schema, and no examples. The description 'Premium API Access' is entirely generic. The broader site lists many endpoints but provides no detail on any of them. Effectively a stub listing.
Warnings
- —No documentation exists for the /api/v1/inbox/125 endpoint — its actual functionality is unknown.
- —No OpenAPI spec, input schema, or example responses are available for any endpoint on this platform.
- —The /pricing and /README pages returned only a 'Connect wallet' prompt with no content.
- —The 'Premium API Access' label is generic and does not describe what the endpoint does.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/inbox/125
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/inbox/125