x402-gated product endpoint on Base, pay $0.02 per request in USDC — no API keys required.
What it does
lowpaymentfee.com hosts a collection of x402-protocol pay-per-call API endpoints on the Base network, settling in USDC. The specific endpoint `/api/v1/products/100` is listed as "Premium API Access" and returns a standard x402 402 challenge when called without payment. The site advertises a flat $0.02 per request across all its endpoints, with no API keys, no rate limits, and no minimum commitments.
The provider offers endpoints spanning several 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 endpoints follow the same x402 payment flow on Base using USDC (contract 0x8335…2913).
The probed endpoint at `/api/v1/products/100` returned a valid x402 challenge with `maxAmountRequired` of 20000 base units. USDC uses 6 decimals, so this equals $0.02 — consistent with the site's advertised pricing. The endpoint accepts POST requests and returns `application/json`. No OpenAPI schema, detailed documentation, or example responses were found in the crawl; the docs, pricing, and API pages all rendered only a "Connect wallet" prompt with no substantive content.
Capabilities
Use cases
- —Accessing a premium product data endpoint with per-call USDC micropayments
- —Agent-driven API consumption without pre-registration or API key management
- —Programmatic purchasing of product information via x402 protocol
Fit
Best for
- —Developers or agents wanting zero-signup, pay-as-you-go API access
- —x402-compatible wallets and agent frameworks on Base
- —Low-cost per-request data retrieval without subscription overhead
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-throughput batch workloads where per-request pricing may add up
- —Users without a Base-compatible USDC wallet
Quick start
# 1. Send a POST to get the 402 challenge
curl -X POST https://lowpaymentfee.com/api/v1/products/100
# 2. Parse the 402 JSON, construct an X-PAYMENT header
# using your x402 client library, then retry:
curl -X POST https://lowpaymentfee.com/api/v1/products/100 \
-H "X-PAYMENT: <signed-payment-token>"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/products/100",
"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 OpenAPI schema, no documentation beyond a landing page listing, no example request/response payloads for the actual paid content, and the docs/pricing/API pages are empty (just 'Connect wallet'). The purpose of 'products/100' is unclear beyond the generic label 'Premium API Access'.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —Docs, pricing, and API pages render only 'Connect wallet' with no substantive content
- —The actual response payload after successful payment is unknown — no examples or schema provided
- —The specific purpose of /api/v1/products/100 is not documented beyond the label 'Premium API Access'
Citations
- —The site advertises $0.02 per request 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 (6 decimals = $0.02) on Basehttps://lowpaymentfee.com/api/v1/products/100
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/products/100