Pay-per-call premium API access on Base via x402 — $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. It is one of many endpoints offered by the provider, which spans categories including data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, payable in USDC on the Base network with no API keys, no rate limits, and no commitments required.
The specific endpoint `/api/v1/charges/40` is listed as "Premium API Access" but its exact functionality is not documented beyond that label. The provider's homepage lists sibling endpoints for metrics, reports, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point. The x402 challenge confirms the endpoint is live, accepts POST requests, settles in USDC (contract 0x8335…) on Base, and requires a maximum payment of 20,000 base units (i.e., $0.02 given USDC's 6 decimals).
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 usage examples available. The endpoint is confirmed live via the 402 challenge, but without documentation it is unclear what request body to send or what response to expect.
Capabilities
Use cases
- —Accessing premium API functionality with per-request USDC micropayments
- —Agent-driven API consumption without pre-registration or API keys
- —Testing x402 payment protocol integrations on Base
Fit
Best for
- —Developers experimenting with x402 pay-per-call patterns
- —Agents that need keyless, on-demand API access
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation before integrating
- —High-volume use cases where per-request pricing may add up
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/40 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge and pricing is clear ($0.02 USDC on Base). However, there is no documentation, no OpenAPI spec, no request/response schema, and the exact functionality of this specific endpoint (/api/v1/charges/40) is undocumented. The docs pages all render only 'Connect wallet' with no content.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet'
- —No OpenAPI or request/response schema provided
- —The exact functionality of /api/v1/charges/40 ('Premium API Access') is not described anywhere
- —This endpoint does not appear in the provider's own listed API catalog on the homepage
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Endpoint is live and returns a 402 x402 challenge requiring USDC payment on Base with maxAmountRequired of 20000 base unitshttps://lowpaymentfee.com/api/v1/charges/40
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/charges/40
- —Provider lists endpoints across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com