Pay-per-call API platform on Base (USDC) covering 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 settled in USDC on the Base network. The specific endpoint at `/api/v1/transactions/123` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) per call. No API keys or rate limits are advertised — callers simply attach an X-PAYMENT header to pay and receive a response.
The platform organizes its endpoints 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/request pricing. The x402 challenge specifies the "exact" payment scheme, a 300-second timeout, and targets the USDC contract on Base (0x8335…2913).
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 crawl. The specific behavior of the `/api/v1/transactions/123` endpoint — what input it expects and what data it returns — is not documented anywhere in the crawled material.
Capabilities
Use cases
- —Agents that need on-demand AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data such as token quotes, exchange rates, or gas estimates via micropayment
- —Running geocoding, validation, or data conversion tasks with per-request billing
Fit
Best for
- —AI agents needing keyless, pay-per-call access to a variety of utility endpoints
- —Developers who want to avoid subscription commitments and pay only for actual usage
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads where $0.02/request adds up significantly compared to subscription APIs
- —Users who need detailed API documentation, SDKs, or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/123 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, documentation is effectively nonexistent — all doc pages show only 'Connect wallet' with no schemas, examples, or descriptions of what the endpoint actually does. The specific purpose of /api/v1/transactions/123 is unclear beyond the label 'Premium API Access'. No OpenAPI spec is available.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) are all blank beyond a 'Connect wallet' prompt — no usable technical docs exist
- —The specific endpoint /api/v1/transactions/123 is not listed among the catalog endpoints on the homepage; its purpose and expected input/output are unknown
- —No OpenAPI spec, request schema, or response schema is available
- —No examples of successful responses are documented anywhere in the crawled material
Citations
- —The x402 challenge requests maxAmountRequired of 20000 base units of USDC (USD Coin) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/123
- —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 endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/123