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 pay-per-call endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities. Every endpoint costs $0.02 per request, settled in USDC on the Base network. There are no API keys, no rate limits, and no subscriptions — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/apikeys/36` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) on Base. The payment is made to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the exact-amount scheme. The endpoint accepts POST requests and returns `application/json`.
The broader platform advertises additional endpoints including 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 spec, request/response schemas, or usage examples are available from the crawled material.
Capabilities
Use cases
- —Agents that need on-demand API access without managing API keys or subscriptions
- —Programmatic access to a variety of utility and data endpoints with crypto micropayments
- —Testing x402 payment protocol integrations against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment-gated APIs
- —AI agents that can settle USDC payments on Base per-call
- —Use cases requiring low-friction, keyless API access at $0.02/request
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume callers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/apikeys/36 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page, and no examples. The purpose of the specific '/api/v1/apikeys/36' endpoint labeled 'Premium API Access' is unclear — it may generate API keys or serve as a generic access point, but nothing in the crawl clarifies this.
Warnings
- —No OpenAPI or schema documentation available — all docs/pricing/README pages return only 'Connect wallet' with no content
- —The specific purpose of /api/v1/apikeys/36 ('Premium API Access') is ambiguous; it is not listed among the catalog endpoints on the landing page
- —No request body schema or response schema is documented anywhere in the crawled material
- —The broader catalog of endpoints (AI, finance, utils) is advertised but none were individually probed
Citations
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge requests maxAmountRequired of 20000 base units of USDC (USD Coin) on Basehttps://lowpaymentfee.com/api/v1/apikeys/36
- —Payment address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 and asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/apikeys/36
- —The platform advertises endpoints for analytics, AI/ML, finance/Web3, and infrastructure utilitieshttps://lowpaymentfee.com