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 specific resource path is /api/v1/charges/304, which is one of many endpoints offered by the provider. The site advertises a broad catalog spanning 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).
Payment is settled on-chain via USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base. The x402 challenge advertises a maxAmountRequired of 20000 base units, which at 6 decimals equals $0.02 per request — consistent with the site's stated flat pricing of $0.02/request across all endpoints. The scheme is "exact", meaning the caller pays the precise amount per call. No API keys are required; access is granted purely through the x402 payment header. The provider claims no rate limits and instant access.
Important caveats: the specific endpoint /api/v1/charges/304 is not individually documented on the site's landing page, and the docs, pricing, API, and README pages all returned only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no documentation describing what this particular endpoint returns or what input it expects beyond a POST with an HTTP body. The provider's catalog is broad but entirely undocumented beyond endpoint names and one-line labels.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without managing API keys or subscriptions
- —Agent-driven workflows that need on-demand API calls settled in USDC on Base
- —Testing x402 payment flows against a live endpoint with low per-call cost
Fit
Best for
- —Developers experimenting with x402 protocol integrations
- —AI agents that need keyless, pay-per-use API access on Base
- —Low-volume or sporadic API consumers who prefer no subscription commitments
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume production workloads requiring well-documented schemas and error handling
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/304 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02/request in USDC on Base), but there is zero documentation for this specific endpoint — no OpenAPI schema, no request/response examples, and no description of what it actually returns. The docs pages are empty. The endpoint path (/api/v1/charges/304) doesn't match any of the advertised catalog endpoints, making its purpose unclear.
Warnings
- —No documentation available — docs, pricing, API, and README pages all return only 'Connect wallet' with no content
- —The specific endpoint /api/v1/charges/304 is not listed among the provider's advertised API catalog; its purpose is unknown
- —No OpenAPI schema, no request/response examples, and no error handling documentation
- —The broad catalog claims (AI, finance, analytics, infrastructure) are entirely unverifiable from available material
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units in USDC on Base networkhttps://lowpaymentfee.com/api/v1/charges/304
- —The site advertises $0.02/request flat pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/charges/304
- —The provider lists endpoints across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com