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/keys/36` is labeled "Premium API Access" and charges up to 20,000 base units of USDC (i.e., $0.02) per call via the x402 exact payment scheme. No API keys, subscriptions, or rate limits are advertised — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
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 `/api/v1/keys/36` endpoint's exact purpose is not documented beyond "Premium API Access," so it may serve as a key-provisioning or meta-access endpoint rather than a domain-specific data call.
Payments are made to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) on Base mainnet. The x402 challenge specifies a 300-second payment timeout. No OpenAPI schema, detailed request/response documentation, or usage examples were found in the crawl.
Capabilities
Use cases
- —Agent-driven data retrieval with per-call USDC micropayments
- —On-demand AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto quotes, gas estimates, and exchange rates via pay-as-you-go calls
- —Geocoding and data validation utilities for automated pipelines
Fit
Best for
- —AI agents needing frictionless, keyless API access with crypto micropayments
- —Developers who want pay-per-use pricing without subscriptions or rate limits
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume batch workloads where per-call pricing becomes expensive compared to flat-rate plans
- —Users without a Base-compatible USDC wallet or x402 client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/36 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response documentation, no examples, and the specific function of /api/v1/keys/36 is undocumented beyond its title. The crawl yielded only a landing page listing endpoints with no deeper docs.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The specific purpose of /api/v1/keys/36 ('Premium API Access') is unclear — it may be a meta/key-provisioning endpoint rather than a data endpoint
- —No request body or response body examples found in crawl
- —Pricing and /api pages returned only 'Connect wallet' with no useful content
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/36
- —All listed endpoints are priced at $0.02 per request with no API keys, rate limits, or commitmentshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/keys/36
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com