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 & 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 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/18` 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, /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, and no examples available. It is unclear what specific data or functionality this particular endpoint (/api/v1/charges/18) returns, as the site's landing page lists many different API categories but does not map charge IDs to specific services. Agents should treat this as a generic paid endpoint until more documentation surfaces.
Capabilities
Use cases
- —Paying per-call for API access without needing an API key or subscription
- —Programmatic agent-driven access to paid endpoints using x402 protocol
- —Accessing data, AI, finance, or utility APIs with USDC micropayments on Base
Fit
Best for
- —Agents or developers wanting keyless, pay-per-use API access
- —x402-compatible wallets and clients on Base
- —Low-volume or sporadic API consumers who prefer no commitments
Not for
- —Users needing detailed API documentation or schemas before integrating
- —High-volume consumers who need bulk pricing or rate guarantees
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/18 \
-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 no clarity on what this specific charge ID returns. Effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet'
- —No OpenAPI or schema provided; request and response formats are unknown
- —The specific functionality of /api/v1/charges/18 ('Premium API Access') is not described anywhere
- —Cannot determine what data or service this endpoint actually provides
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/charges/18
- —All listed APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The site offers APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /pricing, /api, /README) render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs