Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that provides a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/payments/400` is labeled "Premium API Access" and charges up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys or rate limits are advertised; callers simply attach an x402 payment header to each request.
The platform organizes its APIs into 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 listed endpoints share the same $0.02 per-request pricing.
Documentation is extremely sparse — the docs, API, pricing, 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 crawled content. The x402 challenge confirms the endpoint is live and accepts POST requests, but the actual behavior and response format of `/api/v1/payments/400` specifically is unclear from available materials.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, exchange rates, and gas estimates on a per-call basis
- —Running data analytics queries and exporting data with instant crypto-settled micropayments
- —Using utility services like geocoding, validation, and conversion without subscription commitments
Fit
Best for
- —Agents or developers who want zero-signup, pay-as-you-go API access
- —Projects already operating on the Base network with USDC
- —Low-volume or sporadic API usage where subscriptions are wasteful
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume production workloads where per-request pricing at $0.02 may add up quickly
- —Developers without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/400 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and confirms pricing and network details, but documentation is effectively nonexistent — all doc pages show only 'Connect wallet'. No OpenAPI spec, no request/response schemas, and no examples are available. The purpose of the specific /api/v1/payments/400 endpoint is unclear beyond its label.
Warnings
- —Documentation pages (docs, API, pricing, README) all render only 'Connect wallet' with no usable content
- —No OpenAPI or schema documentation available for any endpoint
- —The specific purpose and expected input/output of /api/v1/payments/400 ('Premium API Access') is not documented — it may be a generic or demo endpoint
- —No information on what data sources back the analytics, AI, or finance endpoints
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/payments/400
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers APIs in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/payments/400