Pay-per-call API platform on Base via x402 — $0.02/request for data, AI, finance, and utility endpoints.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad suite of endpoints across 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 endpoints are priced at $0.02 per request and settle in USDC on the Base network.
The specific endpoint at `/api/v1/charges/47` is listed as "Premium API Access" and advertises a max amount of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is handled via the x402 protocol's `exact` scheme — callers attach an `X-PAYMENT` header with a signed payment to the payTo address. No API keys or rate limits are advertised; access is instant once payment is included.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional content. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The endpoint is confirmed live (returns 402 with a valid x402 challenge), but without documentation it is unclear what request body this specific endpoint expects or what response it returns.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key signup
- —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 payments
- —Using utility services like geocoding and validation without rate limits or subscriptions
Fit
Best for
- —Agents and bots that need instant, keyless API access via crypto payments
- —Developers prototyping with low-cost per-request pricing on Base
- —Web3-native applications that prefer on-chain settlement over traditional billing
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume production workloads where $0.02/request adds up significantly
- —Teams that require traditional authentication, SLAs, or enterprise support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/47 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-signed-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, and the landing page lists available endpoints with pricing. However, documentation pages are empty (all show only 'Connect wallet'), there is no OpenAPI spec, no request/response schemas, and no examples. The specific purpose of /api/v1/charges/47 ('Premium API Access') is unclear — it may be a generic charge endpoint rather than a specific functional API. This is effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, API, and README pages all render only 'Connect wallet'
- —No OpenAPI or schema definition found for any endpoint
- —The specific function of /api/v1/charges/47 ('Premium API Access') is ambiguous — unclear what it does beyond accepting payment
- —No request or response examples available anywhere in crawled content
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Endpoint returns 402 with x402 challenge requiring X-PAYMENT header, maxAmountRequired of 20000 base units USDC on Basehttps://lowpaymentfee.com/api/v1/charges/47
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/charges/47
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com