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/charges/334` is listed as "Premium API Access" and costs $0.02 per call (20,000 base units of USDC with 6 decimals). Payment is handled via the x402 protocol — no API keys, no subscriptions, and no rate limits. Callers attach an X-PAYMENT header with a valid payment proof and receive a JSON response.
The wider platform advertises four endpoint 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.
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawl. The endpoint is confirmed live (returns a proper 402 challenge), but without documentation it is unclear what request body `/api/v1/charges/334` expects or what it returns.
Capabilities
Use cases
- —Agents needing on-demand API access without managing API keys or subscriptions
- —Programmatic access to AI inference (sentiment, summarization, classification, embeddings) with per-call billing
- —Fetching real-time financial data (prices, exchange rates, gas estimates) via micropayments
- —Utility operations like geocoding, validation, and data conversion paid per request
Fit
Best for
- —AI agents that need keyless, pay-as-you-go API access on Base
- —Developers prototyping with low-cost per-call endpoints without signup
- —Web3-native applications that already hold USDC on Base
Not for
- —High-volume production workloads where per-call pricing adds up quickly
- —Users who need detailed API documentation, SLAs, or guaranteed uptime
- —Anyone without a Base-compatible wallet or USDC holdings
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/334 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response documentation, no examples, and all doc pages render only 'Connect wallet'. The specific purpose of /api/v1/charges/334 ('Premium API Access') is undifferentiated from the other endpoints and unexplained.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README pages all show only 'Connect wallet'
- —No OpenAPI or schema definition found for any endpoint
- —The purpose and expected input/output of /api/v1/charges/334 specifically is unknown
- —The broad catalog of endpoints (AI, finance, data, utils) is listed but none have documented schemas or examples
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/charges/334
- —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 address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/charges/334