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 & 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 commitments required.
The specific endpoint `/api/v1/charges/63` 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), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme by including an X-PAYMENT header. The endpoint accepts POST requests and returns application/json responses. The payment timeout is 300 seconds.
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 documentation, and no examples of what data this specific endpoint returns. The site's landing page lists many API paths but provides no detail on request parameters or response formats. Without additional documentation it is unclear what specific functionality the `/api/v1/charges/63` path provides versus the named endpoints listed on the homepage.
Capabilities
Use cases
- —Accessing pay-per-request API services without needing API keys or subscriptions
- —Making micropayment-gated API calls settled in USDC on Base
- —Integrating x402-compatible agents with low-cost per-call endpoints
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents with x402 payment capabilities on Base
- —Users who prefer crypto micropayments over traditional API subscriptions
Not for
- —Users needing detailed API documentation or guaranteed SLAs
- —Applications requiring free or non-crypto payment methods
- —Use cases where the specific response schema must be known in advance
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/63 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, and no explanation of what this specific endpoint (/api/v1/charges/63) actually returns. The listing is effectively a stub.
Warnings
- —No documentation available — all doc/pricing/API/README pages render only 'Connect wallet'
- —No OpenAPI or schema definition found
- —The specific endpoint path /api/v1/charges/63 does not match any of the named APIs listed on the homepage, making its purpose unclear
- —No example requests or responses available
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/charges/63
- —Site lists APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com