x402-gated premium API access on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" behind an x402 paywall on the Base network. The site hosts a broad catalog of pay-per-call 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, settled in USDC on Base with no API keys, no rate limits, and no minimum commitments required.
The specific endpoint `/api/v1/charges/305` is labeled "Premium API Access" in the x402 challenge. The challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is via the x402 exact scheme with a 300-second timeout. The endpoint accepts HTTP POST and returns 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, and no examples available. It is unclear what specific data or functionality the `/api/v1/charges/305` endpoint returns, as the site's landing page does not list this particular path among its catalog. The endpoint is live (402 challenge confirmed), but without documentation the actual payload and use case remain unknown.
Capabilities
Use cases
- —Paying per-call for API access without API keys or subscriptions
- —Programmatic access to data/analytics/AI/finance endpoints via x402 protocol
- —Agent-driven API consumption with on-chain USDC micropayments
Fit
Best for
- —Developers wanting keyless, pay-as-you-go API access
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or schemas before integrating
- —High-volume use cases where per-request pricing may add up
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/305 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is no documentation, no OpenAPI spec, no request/response schema, and no examples. The specific purpose of /api/v1/charges/305 is not explained anywhere in the crawled material. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README pages all show only 'Connect wallet' with no content
- —No OpenAPI or schema definition found for this endpoint
- —The specific path /api/v1/charges/305 is not listed among the site's advertised API catalog, making its purpose unclear
- —No request body schema or response schema available — callers cannot know what to send or expect back
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 (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with 300-second timeouthttps://lowpaymentfee.com/api/v1/charges/305
- —Site offers APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com