x402-gated premium API access on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" behind an x402 paywall on the Base network. The site advertises a broad suite of API categories — data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all priced at $0.02 per request with no API keys, no rate limits, and instant access via USDC payments on Base.
The specific endpoint `/api/v1/charges/8` returns a valid x402 challenge (version 1, scheme "exact") requesting up to 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals = $0.02) per call. Payment is sent to address 0x1A2B…85F3 with a 300-second timeout. The endpoint accepts HTTP POST and returns application/json.
However, the exact functionality behind this particular `/charges/8` route is unclear. The site's landing page lists many endpoints across different domains (sentiment analysis, summarization, geocoding, price feeds, etc.), but none of them map directly to `/api/v1/charges/8`. No OpenAPI spec, detailed documentation, or example request/response payloads were found — the docs, pricing, and README pages all rendered only a "Connect wallet" prompt with no substantive content. Without knowing what this specific endpoint returns, callers should treat it as an opaque premium resource.
Capabilities
Use cases
- —Programmatic access to a premium API resource paid per-call in USDC on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API consumption
- —Testing x402 payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that can settle USDC on Base for per-call API access
- —Low-friction API consumption without API key management
Not for
- —Users who need detailed documentation or guaranteed SLAs before integrating
- —Anyone without a Base-compatible USDC wallet
- —High-volume use cases where per-call crypto payments add unacceptable latency
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/8 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but the actual functionality behind /api/v1/charges/8 is undocumented. No OpenAPI spec, no example requests/responses, and the docs pages are empty. The listing is effectively a stub with only pricing and protocol details confirmed.
Warnings
- —The specific functionality of /api/v1/charges/8 is unknown — it does not correspond to any endpoint listed on the site's landing page.
- —Documentation pages (/docs, /pricing, /README, /api) contain no substantive content beyond a 'Connect wallet' prompt.
- —No OpenAPI spec or request/response schema is available.
- —The site lists many endpoints across diverse categories but provides no detailed docs for any of them.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/charges/8
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/charges/8
- —Site advertises $0.02 per request, no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —Site lists endpoints across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com