Pay-per-call premium API endpoint on Base via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. This specific endpoint (`/api/endpoint-31`) is listed as "Premium API Access" and accepts USDC payments at a maximum cost of $0.02 per request (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader lowpaymentfee.com platform advertises endpoints across four 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 listed endpoints share the same $0.02/request pricing. However, this particular endpoint path (`/api/endpoint-31`) does not correspond to any of the named endpoints on the site's landing page, so its exact functionality is unclear.
The endpoint is live and returns a proper 402 challenge. Payment settles on the Base L2 network using USDC (contract 0x8335…2913) to address 0x1A2B…85F3. The x402 version is 1 with a maximum timeout of 300 seconds. No OpenAPI schema, detailed documentation, or example responses were found — the docs, pricing, and API pages all render only a wallet-connect prompt with no additional content.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint without needing API key registration
- —Agent-driven workflows that pay per call using USDC on Base
- —Testing x402 payment protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment flows
- —AI agents that need keyless, pay-as-you-go API access
- —Low-cost per-request API consumption settled on Base
Not for
- —Users who need detailed documentation or guaranteed SLAs before integrating
- —Anyone requiring a specific, well-documented API capability (endpoint function is unclear)
- —High-volume use cases where $0.02/request adds up without volume discounts
Quick start
curl -X POST https://lowpaymentfee.com/api/endpoint-31 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Example
Request
{
"url": "https://lowpaymentfee.com/api/endpoint-31",
"body": {},
"method": "POST",
"headers": {
"X-PAYMENT": "<x402-payment-proof>",
"Content-Type": "application/json"
}
}Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02/request. However, the specific endpoint path (/api/endpoint-31) doesn't match any named endpoint on the site, its actual functionality is unknown, there is no OpenAPI schema, no documentation beyond a wallet-connect prompt, and no example responses are available.
Warnings
- —Endpoint path /api/endpoint-31 does not match any of the named endpoints listed on the landing page — its actual functionality is unknown.
- —No OpenAPI schema or detailed documentation available; docs/pricing/API pages only show a wallet-connect prompt.
- —No example response data available to confirm what this endpoint returns.
- —The site lists many endpoint categories (AI, finance, data, infrastructure) but it is unclear which, if any, this endpoint corresponds to.
Citations
- —The endpoint returns a 402 challenge with x402Version 1, accepting USDC on Base network with maxAmountRequired of 20000 base unitshttps://lowpaymentfee.com/api/endpoint-31
- —All listed endpoints are priced at $0.02/request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 and payTo address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3https://lowpaymentfee.com/api/endpoint-31