Pay-per-call API platform on Base via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API marketplace that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are pay-per-request using USDC on the Base network, settled via the x402 protocol. There are no API keys, no rate limits, and no minimum commitments — callers simply attach an X-PAYMENT header with a valid x402 payment proof to access any endpoint.
The specific endpoint at `/api/v1/charges/43` is listed as "Premium API Access" and requires a maximum of 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this translates to $0.02 per request. The endpoint accepts POST requests and returns application/json. The broader platform advertises additional endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point.
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 schema, no request/response examples, and no detailed documentation for what this specific endpoint actually returns or what input parameters it expects. The endpoint is confirmed live (returns a proper 402 challenge), but without documentation it is unclear what data or functionality "Premium API Access" specifically provides.
Capabilities
Use cases
- —Accessing paid API endpoints without traditional API key registration
- —Making one-off API calls with per-request USDC micropayments on Base
- —Agent-driven workflows that need frictionless pay-as-you-go API access
Fit
Best for
- —Developers who want zero-signup, pay-per-use API access
- —AI agents that can settle x402 payments autonomously on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume callers who would benefit from bulk pricing or subscriptions
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/43 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge and clear pricing ($0.02 USDC on Base). However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI schema, no request/response examples, and no description of what 'Premium API Access' actually returns. The listing is effectively a stub.
Warnings
- —No documentation available — all doc/pricing/README pages render only 'Connect wallet'
- —No OpenAPI or request/response schema provided
- —The purpose of 'Premium API Access' at /api/v1/charges/43 is unclear — no description of inputs or outputs
- —Cannot verify what data or functionality this specific endpoint 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 (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/charges/43
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Docs, API, pricing, and README pages all show only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs