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, payable in USDC on the Base network with no API keys, rate limits, or commitments required.
The specific endpoint `/api/v1/payments/132` returns a valid x402 challenge (HTTP 402) requesting payment of up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) to the address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` on Base. The payment scheme is "exact" with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.
However, the specific functionality behind this particular endpoint path (`/payments/132`) is not documented beyond the generic label "Premium API Access." The provider's landing page lists numerous other endpoints (metrics, reports, sentiment analysis, summarization, classification, embeddings, price feeds, exchange rates, geocoding, etc.) but does not describe `/api/v1/payments/132` specifically. Documentation pages (`/docs`, `/pricing`, `/README`) returned only a "Connect wallet" prompt with no substantive content. Without further documentation, it is unclear what data or service this specific endpoint returns upon successful payment.
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 USDC on Base
- —Testing x402 payment protocol integrations
Fit
Best for
- —Developers or agents wanting keyless, pay-per-use API access
- —x402 protocol experimentation on Base
- —Low-cost per-request API consumption ($0.02/call)
Not for
- —Users who need detailed documentation about what the endpoint actually returns
- —High-volume use cases where per-request crypto payments add latency or cost overhead
- —Users without access to USDC on the Base network
Quick start
# 1. Send a POST to discover the x402 payment challenge:
curl -X POST https://lowpaymentfee.com/api/v1/payments/132
# Returns 402 with X-Payment challenge in JSON body.
# 2. Construct and attach an X-PAYMENT header with a valid
# USDC payment proof on Base, then re-send the POST.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/132",
"description": "Premium API Access",
"maxAmountRequired": "20000",
"maxTimeoutSeconds": 300
}
],
"x402Version": 1
}Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation explaining what this specific endpoint actually does or returns upon successful payment. The docs, pricing, and README pages are all empty beyond a wallet-connect prompt. The listing is essentially a stub with confirmed liveness but unknown functionality.
Warnings
- —The specific functionality of /api/v1/payments/132 is undocumented — the label 'Premium API Access' is generic and uninformative.
- —All documentation pages (/docs, /pricing, /README) returned only 'Connect wallet' with no substantive content.
- —No OpenAPI spec, request schema, or response schema is available.
- —It is unclear how this endpoint relates to the other documented endpoints on the provider's landing page.
Citations
- —The provider lists endpoints across data & analytics, AI & ML, finance & Web3, and infrastructure categories, all priced at $0.02/request.https://lowpaymentfee.com
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Base network.https://lowpaymentfee.com/api/v1/payments/132
- —USDC asset address on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.https://lowpaymentfee.com/api/v1/payments/132
- —Pricing is $0.02 per request with no API keys, no rate limits, and instant access.https://lowpaymentfee.com