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 `/api/v1/keys/94` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). Payment is handled via the x402 protocol — no API keys, accounts, or subscriptions are required; callers attach an X-PAYMENT header with each request.
The 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 per-request pricing. The probe confirmed the endpoint is live, returning a valid 402 challenge with x402 version 1 and an "exact" payment scheme.
Documentation is minimal — the site's /api, /pricing, and /README pages all resolve to a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available. The exact functionality behind the `/api/v1/keys/94` path (labeled "Premium API Access") is unclear and may serve as a key-generation or access-provisioning endpoint rather than a data endpoint. Prospective users should be aware that without documentation, integration requires experimentation.
Capabilities
Use cases
- —Agent-driven data retrieval with per-call USDC micropayments
- —On-demand AI inference (sentiment, summarization, classification, embeddings) without subscriptions
- —Fetching real-time crypto gas estimates and token quotes
- —Geocoding and data conversion utilities paid per request
Fit
Best for
- —Developers and agents wanting zero-commitment, pay-as-you-go API access
- —Crypto-native workflows that can settle in USDC on Base
- —Prototyping and low-volume use cases where $0.02/call is cost-effective
Not for
- —High-volume production workloads needing guaranteed SLAs and detailed documentation
- —Users without a Base-compatible USDC wallet or x402 client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/94 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"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 schema, no documentation beyond the landing page catalog, and the specific purpose of /api/v1/keys/94 is ambiguous. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — integration requires trial and error
- —The /api, /pricing, and /README pages all return only a 'Connect wallet' prompt with no useful content
- —The exact purpose of /api/v1/keys/94 ('Premium API Access') is unclear — it may be a key provisioning endpoint rather than a data API
- —No examples of request or response payloads are available anywhere in the crawled material
Citations
- —The endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/94
- —All listed 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 in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/keys/94