x402-gated premium API access on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" behind an x402 paywall on the Base network. The site hosts a broad catalog of pay-per-call APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, settled in USDC on Base with no API keys, no rate limits, and no commitments required.
The specific endpoint `/api/v1/charges/11` is labeled "Premium API Access" and returns a valid x402 challenge (version 1, scheme "exact") requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The endpoint accepts HTTP POST and returns application/json.
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what this specific endpoint actually returns. The site's landing page lists many API paths but provides no detail on request parameters or response formats. As a result, while the endpoint is confirmed live and the payment mechanics are clear, the actual functionality behind "Premium API Access" at this particular path is unknown.
Capabilities
Use cases
- —Programmatic access to paid API endpoints without API key management
- —Agent-driven pay-per-call workflows settled in USDC on Base
- —Accessing data, AI, finance, or utility APIs with micropayments
Fit
Best for
- —Developers wanting keyless, pay-per-use API access
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —Applications requiring fiat-only payment rails
- —High-volume use cases where per-request pricing may not be cost-effective
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/11 \
-H "Content-Type: application/json"
# Returns 402 with x402 challenge; attach X-PAYMENT header with valid 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/charges/11",
"description": "Premium API Access",
"maxAmountRequired": "20000",
"maxTimeoutSeconds": 300
}
],
"x402Version": 1
}Endpoint
Quality
The endpoint is confirmed live with a valid x402 challenge and clear pricing ($0.02 USDC on Base). However, there is no documentation, no OpenAPI spec, no request/response schema, and no indication of what data or functionality this specific '/charges/11' path actually provides. The docs pages are empty. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet' with no content
- —No OpenAPI or schema describing request parameters or response format for this endpoint
- —The specific functionality of /api/v1/charges/11 ('Premium API Access') is undefined — it is unclear what it returns after payment
- —The site lists many API paths on its landing page but none have documented request/response contracts
Citations
- —Endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/charges/11
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/charges/11
- —Site lists APIs across data/analytics, AI/ML, finance/Web3, and infrastructure categorieshttps://lowpaymentfee.com