Pay-per-call API suite on Base (USDC) covering AI, analytics, finance, and utilities at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and general-purpose utilities. Every endpoint costs $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no upfront commitments. The x402 payment challenge is returned as a standard 402 response, and callers settle via an on-chain USDC micro-payment before receiving the response.
The probed endpoint (`/api/v2/auth`) is listed as "Premium API Access" and returns a valid x402 challenge requesting up to 20,000 base-unit USDC (i.e., $0.02, since USDC uses 6 decimals). The platform advertises additional endpoints across four categories: Data & Analytics (`/api/v1/analytics/metrics`, `/api/v1/analytics/reports`, `/api/v1/data/export`, `/api/v1/data/insights`), AI & Machine Learning (`/api/v2/ai/sentiment`, `/api/v2/ai/summarize`, `/api/v2/ai/classify`, `/api/v2/ai/embeddings`), Finance & Web3 (`/api/v1/finance/prices`, `/api/v1/finance/rates`, `/api/v1/crypto/quotes`, `/api/v1/crypto/gas`), and Infrastructure utilities (`/api/v1/utils/geocode`, `/api/v1/utils/validate`, `/api/v1/utils/convert`, `/api/v1/utils/generate`). All are listed at the same $0.02 price point.
Documentation is extremely thin — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawl. The endpoint is live and the x402 challenge is well-formed, but the lack of documentation makes it difficult to know what request bodies are expected or what response payloads look like.
Capabilities
Use cases
- —Running AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto token quotes and gas estimates via micro-payments
- —Geocoding or data validation on a per-request payment basis
- —Exporting analytics data or generating reports with no subscription
Fit
Best for
- —Agents or bots that need keyless, pay-as-you-go API access
- —Developers prototyping with low-cost per-call pricing on Base
- —Web3-native applications that prefer on-chain settlement over traditional billing
Not for
- —High-volume production workloads where $0.02/request adds up quickly without bulk discounts
- —Users who need detailed API documentation or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v2/auth \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint works and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schemas, and all documentation pages return only a wallet-connect prompt. The actual behavior of the /api/v2/auth endpoint and the 16+ advertised endpoints is undocumented, making this effectively a stub listing.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README pages all show only 'Connect wallet' with no technical content.
- —No OpenAPI or JSON schema describing request/response formats for any endpoint.
- —The specific purpose of the /api/v2/auth endpoint is unclear — 'Premium API Access' is vague and may be an authentication gateway rather than a data endpoint.
- —No agents.txt or robots.txt found on the domain.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base-unit USDC on Base networkhttps://lowpaymentfee.com/api/v2/auth
- —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 & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v2/auth