Pay-per-request API collection on Base via x402 — data, AI, finance, and utility endpoints at $0.02/call.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. The specific endpoint at `/api/v1/collections/6` is labeled "Premium API Access" and accepts POST requests, settling payments in USDC (USD Coin) on Base. The x402 challenge advertises a maximum amount of 20,000 base units of USDC (6 decimals), which equals $0.02 per request.
The provider's landing page lists 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 further content. There is no OpenAPI schema, no request/response examples, and no detailed documentation for any endpoint. The `/api/v1/collections/6` endpoint itself is live (returns a valid 402 challenge), but what data it actually returns upon successful payment is unknown from the available material.
Capabilities
Use cases
- —Accessing data analytics and reports without API key management
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) on a per-call payment basis
- —Fetching real-time financial data like exchange rates, token quotes, and gas estimates
- —Using utility services like geocoding, validation, and conversion with instant crypto payment
Fit
Best for
- —Agents or developers who want keyless, pay-per-use API access via crypto
- —Quick prototyping without subscription commitments
- —Scenarios where Base-network USDC micropayments are preferred over traditional billing
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume production workloads where $0.02/request adds up and bulk pricing is needed
- —Users without access to USDC on the Base network
Quick start
# The endpoint requires an x402 payment header (USDC on Base, $0.02/call)
curl -X POST https://lowpaymentfee.com/api/v1/collections/6 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC payments on Base at $0.02/request. However, there is no OpenAPI schema, no request/response examples, and all documentation pages are empty beyond a wallet-connect prompt. The actual functionality behind '/api/v1/collections/6' is undocumented — it's unclear what data or service it provides upon payment.
Warnings
- —No API documentation available — docs, pricing, and README pages all show only 'Connect wallet' with no content
- —No OpenAPI or schema definition for any endpoint
- —The specific purpose of /api/v1/collections/6 ('Premium API Access') is not described anywhere — unclear what it returns
- —No request or response examples available
- —Cannot verify what any of the listed endpoints actually do without paying
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/collections/6
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The provider lists four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/collections/6