Pay-per-call premium API on Base via x402 — $0.02/request in USDC, no API keys required.
What it does
This endpoint at lowpaymentfee.com/api/endpoint-99 is one of many pay-per-call APIs offered by the lowpaymentfee.com platform. It is labeled "Premium API Access" but the specific functionality behind this particular endpoint path (/api/endpoint-99) is not documented — the site lists various named endpoints under categories like Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure, but endpoint-99 does not appear among them.
The endpoint is live and responds with a valid x402 payment challenge on POST. It accepts payment via the "exact" scheme on the Base network in USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913). The maxAmountRequired is 20000 base units, which at 6 decimals equals $0.02 per request — consistent with the site's advertised flat pricing of $0.02/request across all endpoints. The payment timeout is 300 seconds.
The platform advertises no API keys, no rate limits, and instant access. All payments settle on the Base L2 network. Documentation pages (/docs, /pricing, /README) returned only a "Connect wallet" prompt with no substantive content, so the actual request/response schema for this endpoint is unknown. Without knowing what endpoint-99 does or what parameters it accepts, callers should treat this as an opaque paid endpoint until more documentation surfaces.
Capabilities
Use cases
- —Programmatic access to a paid API endpoint without needing API key registration
- —Agent-driven workflows that settle per-call payments in USDC on Base
- —Testing x402 payment flows against a live endpoint
Fit
Best for
- —Developers exploring x402 payment protocol integrations
- —Agents that can settle USDC payments on Base L2
- —Users who want pay-as-you-go API access without subscriptions
Not for
- —Users who need detailed API documentation or known input/output schemas before calling
- —Anyone without a Base-compatible USDC wallet
- —High-volume use cases where $0.02/request adds up without bulk discounts
Quick start
curl -X POST https://lowpaymentfee.com/api/endpoint-99
# Returns 402 with x402 payment challenge.
# Include X-PAYMENT header with a valid USDC payment proof on Base to access the endpoint.Example
Response
{
"error": "X-PAYMENT header is required",
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3",
"scheme": "exact",
"network": "base",
"mimeType": "application/json",
"resource": "https://lowpaymentfee.com/api/endpoint-99",
"description": "Premium API Access",
"maxAmountRequired": "20000",
"maxTimeoutSeconds": 300
}
],
"x402Version": 1
}Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, the specific functionality of /api/endpoint-99 is completely undocumented — it does not appear in the site's listed endpoints, and all documentation pages returned only 'Connect wallet' with no content. No input/output schema is available.
Warnings
- —The specific functionality of /api/endpoint-99 is unknown — it is not listed among the site's documented endpoints
- —All documentation pages (/docs, /pricing, /README) returned only 'Connect wallet' with no substantive content
- —No input schema or output schema is documented for this endpoint
- —The endpoint path pattern (endpoint-99) suggests it may be a test or placeholder endpoint
Citations
- —The site advertises $0.02/request flat pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge returns maxAmountRequired of 20000 base units in USDC on Base (equivalent to $0.02)https://lowpaymentfee.com/api/endpoint-99
- —The site lists endpoints under Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories but endpoint-99 is not among themhttps://lowpaymentfee.com