Pay-per-call API platform on Base (USDC) covering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint `/api/v1/inbox/30` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). Payment is handled via the x402 protocol — no API keys, no subscriptions, no rate limits. Callers attach an `X-PAYMENT` header with a signed payment to access the resource.
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 endpoints are listed at the same $0.02/request price point.
Importantly, the probed endpoint (`/api/v1/inbox/30`) does not clearly map to any of the publicly listed API paths. Its purpose is described only as "Premium API Access" with no further documentation, input schema, or example responses available. The platform's docs, pricing, and README pages all resolve to a minimal "Connect wallet" prompt with no additional technical detail. Prospective users should be aware that documentation is extremely sparse and the actual behavior of this endpoint is unknown beyond the x402 challenge metadata.
Capabilities
Use cases
- —Programmatic access to pay-per-call API endpoints without managing API keys or subscriptions
- —Agent-driven workflows that need on-demand API calls settled in USDC on Base
- —Exploring x402 protocol integration for micropayment-gated services
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that can sign USDC payments on Base for per-call API access
- —Low-volume, on-demand API consumption without subscription commitments
Not for
- —Production workloads requiring well-documented, stable API contracts
- —Users who need detailed input/output schemas and example responses before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/30 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no input/output schema, no example requests or responses, and the endpoint path '/api/v1/inbox/30' does not match any publicly listed API. Effectively a stub listing.
Warnings
- —Endpoint path /api/v1/inbox/30 does not correspond to any documented API on the platform's landing page
- —No input schema, output schema, or example responses are available
- —Docs, pricing, and README pages all resolve to a minimal 'Connect wallet' page with no technical content
- —Actual functionality of this endpoint is unknown — 'Premium API Access' is the only description provided
Citations
- —The platform lists endpoints at $0.02/request across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Pricing is $0.02/request with no API keys, no rate limits, instant access, on the Base networkhttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/inbox/30 specifies maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/inbox/30