Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are paid per-request using USDC on the Base network, with no API keys, no rate limits, and no minimum commitments required. The specific endpoint at `/api/v1/payments/35` is labeled "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per call (USDC uses 6 decimals).
The platform advertises a broad catalog of endpoints including sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data export — all at the same $0.02 price point. However, documentation is extremely thin: the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail, schemas, or usage examples. There is no OpenAPI spec, no robots.txt, and no agents.txt. The actual behavior and response format of each endpoint is unknown beyond the x402 challenge metadata.
The endpoint is live and responds with a valid x402 version 1 challenge. Payment is settled on Base using the "exact" scheme to wallet 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The output schema indicates the endpoint accepts HTTP POST requests and is discoverable.
Capabilities
Use cases
- —Paying per-call for API access without managing API keys or subscriptions
- —Programmatic agent-to-service payments using USDC on Base
- —Accessing a variety of data, AI, finance, and utility endpoints with crypto micropayments
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously on Base
- —Users who prefer crypto-native billing over traditional API key management
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where per-request pricing at $0.02 may be costly
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/35 \
-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'. No OpenAPI spec, no request/response schemas, no usage examples. The actual functionality behind 'Premium API Access' at /api/v1/payments/35 is unclear.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all render only 'Connect wallet' with no technical content
- —No OpenAPI specification or request/response schema available
- —The specific functionality of /api/v1/payments/35 ('Premium API Access') is not described anywhere
- —No example requests or responses are available to verify what the endpoint actually returns
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/payments/35
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com