Premium API access via x402 micropayment on Base — $0.02 per request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of endpoints spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. Every endpoint is pay-per-call at $0.02 per request, settled in USDC on the Base network. There are no API keys, no rate limits, and no minimum commitments — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/apikeys/66` is listed as "Premium API Access." Its x402 challenge confirms it is live, accepting POST requests and requiring up to 20,000 base units of USDC (0.02 USD) per call. The payment is routed to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` on Base, using the USDC contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`.
The broader platform advertises 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. However, documentation beyond the landing page is extremely sparse: the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. No OpenAPI schema, request/response examples, or detailed parameter documentation were found.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto token quotes and gas estimates with per-call billing
- —Geocoding or data validation as a utility microservice paid per request
- —Exporting analytics data or generating reports with no subscription commitment
Fit
Best for
- —AI agents that need frictionless, keyless API access via x402 micropayments
- —Developers who want pay-per-use pricing with no rate limits or subscriptions
- —Web3-native applications already operating on the Base network with USDC
Not for
- —Users who need detailed API documentation, schemas, or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk/subscription pricing rather than per-call fees
- —Developers without a Base-compatible USDC wallet or x402 client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/apikeys/66 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and confirms pricing and payment details, but there is effectively no documentation, no OpenAPI schema, no request/response examples, and no explanation of what the /api/v1/apikeys/66 endpoint actually returns. The docs, pricing, and README pages are all blank beyond a wallet-connect prompt. This is essentially a stub listing.
Warnings
- —No API documentation found — /docs, /api, /pricing, and /README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or JSON schema available; request parameters and response format are unknown.
- —The specific purpose of /api/v1/apikeys/66 ('Premium API Access') is unclear — it may generate API keys or serve as a generic access endpoint, but no details are provided.
- —The broader catalog of endpoints (AI, finance, utils) is advertised on the landing page but none were individually probed for liveness.
Citations
- —The x402 challenge returns 402 with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/apikeys/66
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC contract address on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/apikeys/66