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/326` 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 the specified wallet address. The endpoint accepts POST requests and returns application/json responses. However, the exact functionality behind this particular payments endpoint (ID 326) is not documented — the provider's landing page lists analytics, AI, finance, and utility APIs but does not specifically describe the `/payments/` path.
Documentation is extremely sparse: the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material. The endpoint is confirmed live via the 402 challenge, but what data or service it actually returns after payment remains unclear.
Capabilities
Use cases
- —Accessing premium API data with per-request USDC micropayments on Base
- —Agent-driven API consumption without pre-registration or API keys
- —Programmatic pay-as-you-go access to various data and utility services
Fit
Best for
- —Developers wanting keyless, pay-per-use API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer on-chain USDC micropayments over subscription billing
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/326
# Returns HTTP 402 with x402 challenge.
# Include X-PAYMENT header with valid payment proof to access the resource.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/326",
"description": "Premium API Access",
"maxAmountRequired": "20000",
"maxTimeoutSeconds": 300
}
],
"x402Version": 1
}Endpoint
Quality
The endpoint is confirmed live via a valid x402 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no documentation of what this specific endpoint actually returns after payment, no OpenAPI spec, no request/response examples, and all doc pages are empty. The exact purpose of /api/v1/payments/326 is unknown.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —The specific functionality of /api/v1/payments/326 is undocumented; the provider lists analytics, AI, finance, and utility endpoints but not a 'payments' path.
- —No OpenAPI or schema definition is provided for request or response payloads.
- —Cannot verify what data or service is delivered after successful payment.
Citations
- —All endpoints priced at $0.02/request with no API keys, rate limits, or commitmentshttps://lowpaymentfee.com
- —Provider offers APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/payments/326
- —USDC asset contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/payments/326