Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. It is one of many endpoints offered by the provider, which spans categories including data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no commitments required.
The specific endpoint `/api/v1/payments/255` returns a valid x402 challenge (HTTP 402) requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) per call. Payment is settled on-chain to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the "exact" scheme. The endpoint accepts POST requests and returns `application/json`.
However, the actual functionality behind this specific `/api/v1/payments/255` path is unclear. The provider's landing page lists numerous other endpoints (metrics, reports, sentiment analysis, summarization, geocoding, etc.) but does not describe a "payments/255" resource. No OpenAPI spec, detailed documentation, or example request/response payloads were found in the crawl. The docs, API, pricing, and README pages all rendered only a "Connect wallet" prompt with no substantive content. As a result, while the endpoint is live and the payment mechanism is well-defined, the actual data or service returned after payment remains unknown.
Capabilities
Use cases
- —Programmatic access to a paid API endpoint without traditional API key registration
- —Agent-driven workflows that need to pay per call using on-chain USDC on Base
- —Testing x402 payment protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —AI agents that can settle micropayments on Base
- —Users who want keyless, pay-as-you-go API access
Not for
- —Users who need detailed documentation or guaranteed SLAs before paying
- —Anyone looking for a specific, well-documented service (the actual payload behind this endpoint is undocumented)
- —Free-tier or fiat-only consumers
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/255 \
-H "Content-Type: application/json"
# Returns 402 with x402 challenge; attach X-PAYMENT header with signed USDC payment to access.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/v1/payments/255",
"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, there is no documentation, no OpenAPI spec, no example request/response for the actual paid resource, and the specific purpose of '/api/v1/payments/255' is not described anywhere in the crawled content. The docs pages are empty beyond a wallet-connect prompt.
Warnings
- —The actual functionality of /api/v1/payments/255 is undocumented — the landing page does not list this path among its advertised endpoints.
- —No OpenAPI spec or detailed API documentation was found; all docs/pricing/README pages render only 'Connect wallet'.
- —The purpose and response schema of this endpoint after successful payment are unknown.
Citations
- —All endpoints priced at $0.02/request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0.02 USD) on Basehttps://lowpaymentfee.com/api/v1/payments/255
- —Provider lists endpoints across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com