Pay-per-request premium API access on Base via x402 — $0.02/call in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The site hosts a broad catalog of pay-per-request 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, payable in USDC on the Base network with no API keys, no rate limits, and no minimum commitments.
The specific endpoint `/api/v1/charges/135` is labeled "Premium API Access" and returns a valid x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals), which equals $0.02 per call. Payment is made via the x402 exact scheme, settling to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The response MIME type is 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 documentation, and no examples of what the endpoint actually returns. The site's landing page lists many API paths but provides no detail on input parameters or output formats. Because of this, it is unclear what specific functionality the `/api/v1/charges/135` endpoint provides or how it differs from the other listed endpoints.
Capabilities
Use cases
- —Accessing pay-per-request API services without needing API keys or subscriptions
- —Making low-cost programmatic API calls settled in USDC on Base
- —Agent-driven API consumption with per-call crypto micropayments
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto-native API billing without accounts
Not for
- —Users who need detailed API documentation or schemas before integrating
- —High-volume consumers who need bulk pricing or SLAs
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/135 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, confirming pricing and payment details. However, there is no OpenAPI spec, no documentation beyond a wallet-connect prompt, no request/response schema, and no examples. The purpose of this specific endpoint (/api/v1/charges/135) is unclear. Effectively a stub listing.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The specific function of /api/v1/charges/135 ('Premium API Access') is not explained anywhere
- —No examples of successful responses are available
- —Cannot verify what data or service this endpoint actually provides
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, with 300-second timeouthttps://lowpaymentfee.com/api/v1/charges/135
- —Site lists APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet' with no contenthttps://lowpaymentfee.com/docs