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/64` 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, 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.
Important caveat: the specific `/api/v1/inbox/64` endpoint does not correspond to any of the named endpoints on the landing page. Its purpose and response format are unclear — the description simply says "Premium API Access" with no further documentation. There is no OpenAPI spec, no request/response examples, and the docs, pricing, and README pages all resolve to a wallet-connect prompt with no additional content. Treat this endpoint with caution until more documentation surfaces.
Capabilities
Use cases
- —Programmatic access to a generic premium API endpoint via x402 micropayments
- —Agent-driven workflows that need keyless, pay-as-you-go API access on Base
- —Testing x402 payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —AI agents that need frictionless pay-per-call API access without credentials
- —Low-volume consumers who want no subscription or rate-limit constraints
Not for
- —Users who need well-documented, schema-defined API contracts
- —High-volume production workloads requiring SLAs or support
- —Anyone needing clarity on what the /inbox/64 endpoint actually returns
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/64 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Example
Request
{
"url": "https://lowpaymentfee.com/api/v1/inbox/64",
"body": {},
"method": "POST",
"headers": {
"X-PAYMENT": "<x402-payment-token>",
"Content-Type": "application/json"
}
}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 OpenAPI schema, no documentation of request/response formats, and the /inbox/64 path doesn't match any named endpoint on the site. Effectively a stub listing.
Warnings
- —The /api/v1/inbox/64 path does not match any documented endpoint on the landing page — its purpose is unknown.
- —No OpenAPI spec, request schema, or response examples are available.
- —Docs, pricing, and README pages all resolve to a wallet-connect prompt with no content.
- —The platform lists many endpoint categories but none have detailed documentation.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/64
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/inbox/64
- —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 Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com