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 offers a broad catalog of pay-per-call APIs spanning data & analytics, AI & machine learning (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/158` is labeled "Premium API Access" in the x402 challenge. The challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals), which equals $0.02. Payment is via the x402 exact scheme: callers attach an X-PAYMENT header with a signed payment to the payTo address. The endpoint accepts POST requests and returns application/json.
Documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema, and no examples available. It is unclear what specific data or functionality the `/api/v1/charges/158` endpoint returns, as the site's landing page lists many different API categories but does not map charge IDs to specific services. The endpoint is confirmed live (402 challenge captured successfully).
Capabilities
Use cases
- —Programmatic access to paid API endpoints without needing API keys or subscriptions
- —Agent-driven workflows that need on-demand API calls settled in USDC on Base
- —Testing x402 payment flows with a low-cost endpoint
Fit
Best for
- —Developers or agents wanting keyless, pay-per-use API access
- —x402 protocol integrators looking for a live test endpoint
- —Users who prefer crypto micropayments over traditional billing
Not for
- —Users who need detailed API documentation or well-defined schemas before integrating
- —Anyone requiring non-crypto payment methods
- —Production workloads that need guaranteed SLAs or support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/158 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"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 spec, no request/response schema, no documentation beyond a wallet-connect prompt, and the specific function of /api/v1/charges/158 is undefined. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README pages all show only 'Connect wallet'
- —No OpenAPI or schema definition found
- —The specific functionality of /api/v1/charges/158 ('Premium API Access') is not described anywhere
- —Cannot determine what request body to send or what response to expect
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/charges/158
- —Site lists APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com