Pay-per-call notification endpoint on Base via x402 — $0.02 per request in USDC.
What it does
This endpoint at `/api/v1/notifications/3` is part of the lowpaymentfee.com platform, which offers a suite of pay-per-request APIs spanning data & analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints use the x402 protocol for payment, settling in USDC on the Base network. The specific endpoint probed here is labeled "Premium API Access" and costs $0.02 per request (20,000 base units of USDC with 6 decimals).
The platform advertises a simple model: no API keys, no rate limits, no commitments — just attach an x402 payment header to each call. The endpoint accepts HTTP POST requests and returns `application/json`. However, there is no public OpenAPI schema, no documentation beyond the landing page listing, and no example request/response payloads available. The exact functionality of the `/notifications/3` endpoint is unclear — the name suggests it retrieves or triggers a notification resource, but no further detail is provided in the crawled material.
The broader lowpaymentfee.com platform lists 16 endpoints across four categories (Data & Analytics, AI & Machine Learning, Finance & Web3, Infrastructure), all priced at $0.02 per request. The x402 challenge was successfully captured, confirming the endpoint is live and accepting payment challenges on Base mainnet with USDC (contract `0x8335...2913`).
Capabilities
Use cases
- —Triggering or retrieving notifications via a pay-per-call model without API key management
- —Integrating low-cost notification services into agent workflows that settle payments on Base
- —Testing x402 protocol integrations with a live, inexpensive endpoint
Fit
Best for
- —Developers exploring x402 payment protocol integrations
- —Agents needing simple pay-per-request notification access
- —Projects wanting no-signup, no-API-key access to utility endpoints
Not for
- —Users needing well-documented APIs with full OpenAPI specs and example payloads
- —High-volume notification use cases where per-request pricing adds up quickly
- —Anyone requiring detailed notification customization or guaranteed SLAs
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/notifications/3 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02/request in USDC on Base), but there is no OpenAPI schema, no documentation of request/response formats, and no explanation of what the /notifications/3 endpoint actually does. The listing is essentially a stub with confirmed liveness.
Warnings
- —No OpenAPI or schema documentation available — endpoint behavior must be discovered empirically
- —The exact purpose of /api/v1/notifications/3 is undocumented; 'Premium API Access' is a generic label
- —No example request or response payloads are available from crawled material
- —The /api, /pricing, and /README pages all returned only a 'Connect wallet' prompt with no useful content
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/notifications/3
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers 16 endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/notifications/3