Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. The specific endpoint at `/api/v1/charges/49` is labeled "Premium API Access" and accepts POST requests. Payment is settled in USDC (contract 0x8335…2913 on Base) with a maximum charge of 20,000 base units, which equals $0.02 per request (USDC uses 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader lowpaymentfee.com platform advertises endpoints across four categories: Data & Analytics (metrics, reports, data export, insights), 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 are listed at the same $0.02/request price point. However, the specific endpoint `/api/v1/charges/49` does not clearly map to any of these named services — its description is simply "Premium API Access" with no further documentation on what data or functionality it returns.
Documentation is extremely sparse. The /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI spec, no request/response schema, and no examples of what this endpoint actually returns. The endpoint is confirmed live (returns a proper 402 challenge), but without knowing what it does, callers are essentially paying blind.
Capabilities
Use cases
- —Programmatic access to an unknown premium service at $0.02/call via x402
- —Demonstrating x402 payment protocol integration on Base
- —Agent-driven API consumption without API key management
Fit
Best for
- —Developers experimenting with x402 payment flows on Base
- —Agents that need keyless, pay-per-use API access
- —Testing micropayment infrastructure with low-cost calls
Not for
- —Anyone who needs to know what the endpoint returns before paying
- —Production use cases requiring documented request/response schemas
- —Users without USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/49 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02/request. However, there is zero documentation on what the endpoint actually does, no request/response schema, no examples, and the docs pages are empty. The listing is effectively a stub.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet' with no content
- —No OpenAPI spec or request/response schema provided
- —The endpoint path '/api/v1/charges/49' does not correspond to any of the named services listed on the homepage
- —It is unclear what data or functionality this endpoint returns — callers pay without knowing what they receive
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/charges/49
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/charges/49
- —All listed APIs are priced at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com