x402-gated API suite on Base: analytics, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com offers a collection of pay-per-call API endpoints gated by the x402 protocol on the Base network. The specific endpoint at `/api/v1/charges/312` is labeled "Premium API Access" and accepts payment in USDC (contract 0x8335…2913 on Base). The x402 challenge advertises a maxAmountRequired of 20,000 base units, which at 6 decimals for USDC equals $0.02 per request.
The provider's landing page lists four categories of endpoints: 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 are listed at $0.02 per request with no API keys, no rate limits, and no minimum commitments.
Documentation is extremely sparse — the /docs, /api, /pricing, 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 valid 402 challenge), but without documentation it is unclear what request body this specific `/charges/312` endpoint expects or what response payload it returns.
Capabilities
Use cases
- —Paying per-call for AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data such as token quotes, exchange rates, and gas estimates
- —Running utility operations like geocoding, validation, and data conversion on demand
- —Accessing analytics metrics and reports with crypto micropayments
Fit
Best for
- —Agents or developers who want keyless, pay-per-request API access settled in USDC on Base
- —Low-volume or bursty workloads where subscription pricing is wasteful
- —x402-compatible AI agents that can autonomously pay for API calls
Not for
- —High-volume production workloads needing SLAs, rate-limit guarantees, or detailed documentation
- —Users who need fiat-only payment rails (this endpoint requires USDC on Base)
- —Developers who need well-documented request/response schemas before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/312 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, and the landing page provides a high-level catalog. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The specific purpose of /api/v1/charges/312 is unclear beyond the generic label 'Premium API Access'. This is effectively a stub listing.
Warnings
- —No OpenAPI spec or machine-readable schema available
- —Documentation pages (/docs, /pricing, /README) render only 'Connect wallet' with no content
- —The specific endpoint /api/v1/charges/312 is not listed on the landing page catalog — its exact functionality is unknown
- —No request body schema or response schema documented anywhere in the crawl
- —Cannot verify what data or service this endpoint actually returns
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units in USDC on Base networkhttps://lowpaymentfee.com/api/v1/charges/312
- —USDC contract address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/charges/312
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The site offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —Documentation pages render only a 'Connect wallet' prompt with no further contenthttps://lowpaymentfee.com/docs