Pay-per-call API platform on Base via x402 — data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across four categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, paid in USDC on the Base network via the x402 protocol.
The specific endpoint at `/api/v1/charges/120` is listed as "Premium API Access" and carries a max amount of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The platform advertises no API keys, no rate limits, no minimums, and instant access — payment is handled entirely through the x402 payment header. The probe confirmed the endpoint is live, returning a proper 402 challenge with x402Version 1.
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 spec, no request/response schema documentation, and no examples of what the endpoint actually returns. The name "Premium API Access" and the path `/api/v1/charges/120` do not clearly indicate what data or functionality this specific endpoint provides. Without documentation or example responses, it is unclear what payload to send or what to expect back.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates on a per-call basis
- —Running utility operations like geocoding or data validation with crypto micropayments
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access via crypto
- —Agents or bots that need programmatic API access without signup or API keys
- —Projects already on the Base network looking for cheap per-call services
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk pricing or subscription plans
- —Developers without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/120 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and the landing page provides a catalog overview with pricing. However, there is no OpenAPI spec, no request/response documentation, no examples, and the specific endpoint's purpose ('Premium API Access' at /charges/120) is unclear. All secondary pages render only 'Connect wallet' with no content.
Warnings
- —No API documentation available — /docs, /api, /pricing, and /README pages are empty beyond a wallet connect prompt
- —No OpenAPI or schema definition found for any endpoint
- —The specific purpose of /api/v1/charges/120 ('Premium API Access') is not explained anywhere
- —No example request or response payloads are documented
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Endpoint returns 402 with maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/charges/120
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com