Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The site hosts a collection of pay-per-request APIs spanning data & analytics, AI/ML inference, finance & Web3 data, and infrastructure utilities — all priced at $0.02 per request, settled in USDC on the Base network.
The specific endpoint `/api/v1/charges/383` is labeled "Premium API Access" and accepts POST requests. It requires an x402 payment of up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per call (USDC uses 6 decimals). There are no API keys, no rate limits, and no minimum commitments — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader lowpaymentfee.com platform advertises additional endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, conversion, and data export — all at the same $0.02 price point. However, documentation beyond the landing page is extremely sparse (docs, pricing, and API pages all render only a "Connect wallet" prompt), so the exact request/response schemas for this particular endpoint are unknown. Without concrete documentation on what data this endpoint returns or what input it expects, callers should treat this as an exploratory integration.
Capabilities
Use cases
- —Agent-driven API consumption where per-call crypto micropayments replace traditional API key subscriptions
- —Programmatic access to premium data or services without account registration
- —Testing x402 payment protocol integrations on Base
Fit
Best for
- —Developers or agents wanting zero-signup, pay-as-you-go API access
- —x402 protocol experimenters looking for low-cost endpoints on Base
- —Scenarios requiring no rate limits and instant access without credentials
Not for
- —Users who need detailed API documentation and well-defined schemas before integrating
- —High-volume production workloads where undocumented endpoints pose reliability risks
- —Users without USDC on Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/383 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI schema, no example requests or responses, and no indication of what data or service this specific endpoint actually returns. The docs, pricing, and API pages are all blank beyond a wallet-connect prompt.
Warnings
- —No documentation available — docs, pricing, and API pages all show only 'Connect wallet' with no content
- —The exact purpose and response format of /api/v1/charges/383 ('Premium API Access') is completely undocumented
- —No OpenAPI spec, no input/output schema beyond the x402 outputSchema stub
- —Cannot verify what service is actually delivered after payment
Citations
- —Endpoint returns 402 with x402 challenge requiring up to 20,000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/charges/383
- —All APIs priced at $0.02/request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/charges/383
- —Site lists endpoints for analytics, AI/ML, finance, and infrastructure utilitieshttps://lowpaymentfee.com