Pay-per-call API platform on Base network via x402 — $0.02/request in USDC, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are priced at $0.02 per request, paid in USDC on the Base network via the x402 payment protocol. No API keys, accounts, or rate limits are advertised — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The specific endpoint at `/api/v1/payments/68` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base. The payment is settled to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.
The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — all at the same $0.02 price point. However, documentation beyond the landing page is extremely sparse (docs, pricing, and README pages all render only a "Connect wallet" prompt), so the actual request/response schemas for individual endpoints are unknown.
Capabilities
Use cases
- —Agents needing on-demand API access without pre-registration or API keys
- —Pay-per-call AI inference (sentiment, summarization, classification, embeddings)
- —Fetching real-time crypto token quotes and gas estimates
- —Geocoding and data conversion utilities with micropayments
Fit
Best for
- —AI agents that need frictionless, keyless API access via x402
- —Developers wanting to test x402 payment flows at low cost ($0.02/call)
- —Applications requiring diverse utility endpoints without subscription commitments
Not for
- —High-volume production workloads where per-request pricing adds up quickly
- —Users who need detailed API documentation and well-defined schemas before integration
- —Non-crypto users who cannot settle payments in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/68 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, there is no OpenAPI schema, no request/response documentation, and the docs/pricing/README pages are all empty beyond a wallet-connect prompt. The actual functionality behind 'Premium API Access' at /api/v1/payments/68 is unclear — it could be any of the advertised services or a generic payment test endpoint. Effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, and README pages all render only 'Connect wallet'
- —The specific purpose of /api/v1/payments/68 ('Premium API Access') is not described anywhere; it does not match any of the named endpoints on the landing page
- —No request or response schemas are available for any endpoint
- —Cannot verify what data or service is actually returned after payment
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with 300s timeouthttps://lowpaymentfee.com/api/v1/payments/68
- —Payment address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3https://lowpaymentfee.com/api/v1/payments/68