x402-payable API platform on Base offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API marketplace that exposes a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are pay-per-call using the x402 protocol, settling in USDC on the Base network. The specific endpoint at `/api/v1/cards/80` is listed as "Premium API Access" and accepts POST requests with payment via USDC (contract 0x8335…2913 on Base).
The platform advertises a flat $0.02 per request across its catalog, with no API keys, no rate limits, and no minimum commitments required. The x402 challenge captured for this endpoint shows a `maxAmountRequired` of 20000 base units of USDC (6 decimals), which equals $0.02 — consistent with the site's stated pricing. Categories of endpoints available on the platform include metrics/reports/export/insights (data & analytics), sentiment analysis/summarization/classification/embeddings (AI & ML), price feeds/exchange rates/token quotes/gas estimates (finance & Web3), and geocoding/validation/conversion/generation (infrastructure utilities).
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 this one. The actual functionality behind `/api/v1/cards/80` is unclear from the available material; the description "Premium API Access" is generic and does not specify what data or service is returned.
Capabilities
Use cases
- —Programmatic access to various API services with per-call USDC micropayments
- —Agent-driven workflows that need keyless, on-demand API access
- —Testing x402 payment protocol integrations
Fit
Best for
- —Developers wanting no-signup, pay-per-use API access
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where per-request pricing may add up
- —Anyone requiring fiat-only payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/80 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC payments on Base at $0.02/request. However, there is no documentation, no OpenAPI schema, no request/response examples, and the purpose of `/api/v1/cards/80` specifically is entirely unclear. The docs pages are empty beyond a wallet connect prompt. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format for this endpoint
- —The specific purpose of /api/v1/cards/80 ('Premium API Access') is not explained anywhere
- —Cannot verify what data or service this endpoint actually returns without making a paid request
Citations
- —The platform charges $0.02 per request with no API keys, no rate limits, and no minimumshttps://lowpaymentfee.com
- —x402 challenge shows maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/cards/80
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/cards/80
- —Available API categories include Data & Analytics, AI & ML, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com