x402-gated API suite on Base: analytics, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-protocol API provider offering a broad catalog of pay-per-call endpoints settled in USDC on the Base network. The specific endpoint `/api/v1/cards/7` is listed as "Premium API Access" and requires a payment of up to 20,000 base units of USDC (i.e., $0.02) per request. The x402 challenge was successfully captured, confirming the endpoint is live and accepting POST requests.
The provider's landing page advertises four categories of APIs: 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 listed at $0.02 per request with no API keys, no rate limits, and no minimum commitments required.
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 schema, no request/response examples, and no detailed documentation for any endpoint, including `/api/v1/cards/7`. The purpose and output of the specific `/api/v1/cards/7` endpoint is unclear from available materials; the name "Premium API Access" does not indicate what data or functionality it provides. Without documentation or example payloads, agents will need to experiment to determine the endpoint's actual behavior.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without needing API keys or subscriptions
- —Agent-driven API consumption settled via x402 USDC micropayments on Base
- —Exploring a multi-category API catalog (analytics, AI, finance, utilities) with per-request billing
Fit
Best for
- —Agents that can settle x402 payments in USDC on Base
- —Developers wanting zero-commitment, pay-as-you-go API access
- —Prototyping workflows that need cheap per-call pricing without signup
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume production workloads where per-request crypto settlement adds overhead
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/7 \
-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 zero documentation for the /api/v1/cards/7 endpoint — no schema, no examples, no description of what it returns. The docs, pricing, and README pages are all blank beyond a wallet-connect prompt. The endpoint's actual purpose is unknown.
Warnings
- —No documentation available: /docs, /pricing, /api, and /README pages all show only 'Connect wallet' with no content.
- —The purpose and response format of /api/v1/cards/7 ('Premium API Access') is completely undocumented and unclear.
- —No OpenAPI schema or request/response examples are provided by the provider.
- —No robots.txt or agents.txt found.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/cards/7
- —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 USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/cards/7
- —Documentation pages (/docs, /api, /pricing, /README) render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs