Pay-per-request API collection on Base via x402 — data, AI, finance, and utility endpoints at $0.02/call.
What it does
lowpaymentfee.com offers a suite of pay-per-request APIs accessible via the x402 payment protocol on the Base network. The endpoint at `/api/v1/collections/4` is labeled "Premium API Access" and accepts POST requests with payment in USDC (USD Coin) on Base. The x402 challenge indicates a maximum amount of 20,000 base units of USDC (6 decimals), which equals $0.02 per request.
The provider's landing page advertises four categories of APIs: 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 listed at $0.02 per request with no API keys, no rate limits, and no minimum commitments required.
Documentation beyond the landing page is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no detailed documentation for any of the endpoints. It is unclear what specific data or functionality the `/api/v1/collections/4` endpoint returns versus the individual category endpoints listed on the homepage.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data such as token quotes, gas estimates, and exchange rates on a per-request basis
- —Running data analytics queries and exporting data with instant crypto-settled micropayments
- —Using utility services like geocoding, validation, and conversion without subscription commitments
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle payments autonomously via x402 on Base
- —Projects needing low-cost micropayment-gated endpoints without rate limits
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume production workloads that benefit from bulk pricing or SLAs
- —Developers without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/collections/4 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages are empty beyond a wallet-connect prompt. The purpose of the specific /collections/4 endpoint is unclear. Effectively a stub listing.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content
- —No OpenAPI or schema definition for any endpoint
- —The specific purpose and expected input/output of /api/v1/collections/4 is undocumented
- —Cannot verify whether the advertised AI, finance, and utility endpoints actually function
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/collections/4
- —All endpoints are listed at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Four categories of APIs are advertised: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/collections/4